Disaster Readiness and Risk Reduction Quarter 1 PDF

UNIT 1: THE CONCEPT OF DISASTER AND DISASTER RISK LESSON 1: DISASTER AND DISASTER RISK Concept of Disaster Disaster is a dangerous situation or threat from natural or man-made events that disrupt the functions of individuals in a community. Hazard - a threat to life, environment, or property. Can be...

UNIT 1: THE CONCEPT OF DISASTER AND DISASTER RISK LESSON 1: DISASTER AND DISASTER RISK Concept of Disaster Disaster is a dangerous situation or threat from natural or man-made events that disrupt the functions of individuals in a community. Hazard - a threat to life, environment, or property. Can be considered a disaster if it poses an actual harm to life and environment. Can be classified based on its origins: NATURAL and MAN-MADE. Natural Hazards - caused by abrupt or slow onset of naturally occurring phenomena which can be biological, geological, hydrological, meteorological, and climatological. Natural Hazards​ ​ ​ Description Biological​ ​ ​ ​ Diseases, Epidemics, Plagues Geological​ ​ ​ ​ Earthquakes, Landslides, Tsunamis, Volcanic Activity Hydrological​ ​ ​ ​ Avalanche, Floods Meteorological​​ ​ Storm surges, Cyclones, Tornadoes Climatological​​ ​ Drought, Wildfires MAN-MADE HAZARD - caused by human activities and occur near human settlements. Examples: Pollution, Accident, Arson, War, and etc. Vulnerability - the failure to withstand the impacts of hazards. Mitigation - refers to the act of preventing or minimizing the effects of a disaster by introducing precautionary measures before it strikes a community. NATURAL DISASTER - Natural disasters like typhoons occur with warning. PAGASA (Philippine Atmospheric, Geophysical and Astronomical Services) and the media provide information about the typhoon’s speed and location so that citizens could take precautionary measures and evacuation procedures before the typhoon strikes. LESSON 2: RISK FACTORS UNDERLYING DISASTERS Disaster Risk is defined by United Nations International Strategy for Disaster Reduction (UNISDR) as “the combination of the probability of an event and its negative consequences”. ​ Hazard - any phenomenon that can potentially cause damage to life, property, or environment. ​ Exposure - any element (people, property, or system) that is present in a hazard and is prone to potential loss. ​ Vulnerability - feature of a community that makes them prone and exposed to the negative impacts of hazard. Resilience - the ability of a community to withstand, accommodate, and recover from a disaster. DISASTER RISK FACTORS ​ Physical - this includes the concrete objects in a community that can help or harm an individual during a disaster. ​ Psychological - it includes the mental state of an individual, like the ability of an individual to respond to a disaster or fear. ​ Socio-cultural - includes traditions, religion, and social statuses in society. Ex: presence of bayanihan system, community folklore ​ Economic - this includes resources in the community and the income source of the individuals such as farming and employment. ​ Biological - includes the flora and fauna in the environment, their health, and its diseases. DISASTER RISK REDUCTION Disaster risk reduction aims to decrease the risk level in communities. It implements policies and measures to control potential risks like poor urban and rural planning, poverty, and poor government and local capacities. Disaster risk reduction is implemented in order to: reduce vulnerability to life, property, or environment to an existing hazard; reduce degree of exposure to hazards; and increase preparedness through proper mitigation procedures. LESSON 3: EFFECTS OF DISASTERS According to ChildFund International, 8 out of 10 world cities most at risk to disaster are found in the Philippines. Natural disasters have affected over 4.4 billion people claiming the loss of 1.3 million people and US$ 2 trillion since 1994 (United Nations, 2014). Those are some of the devastating impacts of a disaster. Population - Increased population in evacuation centers is the most immediate effect during a disaster. In the Philippines, the common evacuation areas are schools and churches. Health - One consequence of disaster is threat to the population’s health. Severe flooding caused by typhoons can increase the presence of stagnant water in the area. This stagnant water is a perfect breeding ground for mosquitoes to lay their eggs and for the growth of bacteria. A common disease during a typhoon is leptospirosis, a bacterial disease that affects humans. Food - Food becomes limited after an occurrence of disaster. Food becomes limited after an occurrence of disaster. Sources of food from farms, poultry, and aquaculture become damaged after a disaster, thus the supply of food becomes limited. Psychological - Anyone who has encountered a disaster can be traumatized by its terrible effects. For everyone, but especially for children, exposure to catastrophe and disaster can leave a lasting impression. After going through such stressful experiences, numerous children may acquire post-traumatic stress disorder (PTSD). PTSD is a severe psychological disorder brought on by severe trauma. A lifetime of psychological harm and emotional pain may result from a failure to identify and treat it in a timely manner. FACTORS AFFECTING SEVERITY OF EFFECTS 1.​ Severity of exposure - A person exposed to a more severe disaster has higher risk for mental distress. 2.​ Age - According to research, people between the ages of 40 and 60 are more likely than children to experience catastrophe distress. After a tragedy, adults' mental anguish is exacerbated by other demands, such as their families and work. Children's delayed recovery is correlated with parents' greater levels of stress. Human Resilience - Humans are naturally resilient. Resilience is the ability of individuals to recover from the impacts of a disaster. There are several factors that increase the resilience of an individual: 1. Social support includes emotional support by sharing traumatic experiences, coping mechanisms, and finding a sense of comfort from others. 2. Coping confidence is the self-efficiency to believe that one can survive any disaster and reduce mental distress in the future. This method of coping includes values like optimism, hope, and confidence. LESSON 4: HOW AND WHEN AN EVENT BECOMES A DISASTER Hazard can be considered a disaster when there are already negative impacts to human life and their properties. Hazards are a risk factor in the occurrence of disasters. Thus, a disaster can be prevented if the risk brought by a hazard can be prevented or reduced. For instance, a typhoon is a natural hazard that can be predicted using weather satellites. Its impacts can be reduced if proper mitigation procedures are done such as information dissemination and evacuation before the typhoon strikes in a community. This is called a proactive approach to emergency preparedness. Earthquakes are unforeseen natural hazards due to the movement of plates in the earth’s crust. LESSON 5: AREAS OR LOCATIONS EXPOSED TO HAZARDS The Philippines is geographically located at the “Pacific Ring of Fire”. These are countries that are usually hit by disasters like earthquakes. According to the Center for Research on the Epidemiology of Disasters (CRED), the worst combination of disasters experienced by the Philippines was from 1901 to 2000. The occurrence and effects of disasters are inevitable but reducing the severity can be done by proper mitigation procedures. PREDICTION AND WARNING 1.​ Prediction is a statement of probability of hazards to occur based on a number of evidences or observations. 2.​ A warning is a signal that tells of a high probability of occurrence of a hazard. CLIMATE AND WEATHER RELATED HAZARDS Areas with low elevation are more prone to impacts of typhoons and floods. Also, areas with poor drainage systems, located near bodies of water can be prone to floods as well. Steep landforms with poor vegetation are prone to landslides during typhoons. GEOPHYSICAL RELATED HAZARDS Earthquakes are more prominent in areas near fault lines. We can recall the tectonic plates in the earth’s crust and identify which are the fault lines. Areas that are deep-focused, are prone to earthquakes because of its trench and nearby active faults. MAN-MADE RELATED HAZARDS Fire hazards can be caused by faulty electrical wiring, children playing with matches, candles left unattended, burning garbage, leaking LPG tanks, and using firewood in cooking. War is considered the worst man-made disaster. In the Philippines, the war in Marawi last May of 2017 caused a huge disaster not only to the city’s infrastructure but to the lives of the people living there. LESSON 6: DISASTER FROM DIFFERENT PERSPECTIVE Physical and Environmental Impact When a disaster hits, the first line of impact is the environment. Disaster causes drastic changes in the structure of the environment. For example, when an earthquake occurs in an area, there is a high possibility that roads will break and crack. Landslides in the mountains cause erosion of the soil. This will lead to the removal of an arable layer of soil. Socio-Economic Aspect Impacts of disaster in the socio-economic aspect include the state of the social well-being and the financial resources of the community. Government agencies are responsible for reducing the socio-economic impacts of the community through proper mitigation procedures. Developing nations like the Philippines are more susceptible to socioeconomic effects, according to recent studies. One explanation is that poor nations' higher vulnerability and lack of resilience make them more vulnerable to the effects of disasters. Developing nations are more vulnerable due to their low economic standing, hence appropriate budgetary allocation is a necessary component of mitigation strategies. Educational Aspect Reducing the dangerous impacts of catastrophes requires information access. In addition to being crucial for determining disaster risk, observation and data analysis are also necessary for teaching and training individuals on disaster risk reduction. The number of elementary and high school students is higher. When it comes to disaster management, a community's high literacy rate is essential. Psychological Aspect A natural or man-made disaster is a traumatic event that can cause stress, depression, and anxiety. People with underlying mental illnesses are considered a vulnerable group. Shock and denial stages after disastrous events are normal for victims that is why they need psycho-social intervention to be able to cope and live a normal life. Biological Aspect Disasters can cause health problems to individuals. On a larger scale, these diseases can cause an epidemic or an outbreak especially if emergency care is not available. In terms of biological diversity, animals, and plants that live in a community where disaster strikes can drastically decrease in number. This would result in an imbalance in the ecosystem and potentially limited access to food resources, agriculture, and livestock. Political Aspect A disaster may also change the way citizens feel about other people in general, like after giving donations to assist affected individuals. A disaster may also affect public opinion about the government, because citizens can feel and see how the government handled the effects of the disaster. In that respect, potential social and political effects of disasters occur through direct and indirect experiences. CREDITS MISSY ANAGAP CUTE? Unit 2 :Exposure and Vulnerability LESSON 1 : Vulnerability Vulnerability, according to the UNDRR’s 2014 list of terminologies, is a set of characteristics and circumstances, systems, or assets that make it susceptible to the damaging effects of hazards. ​ One of the determinants of the effects and impacts of hazards. ​ Affects how people live, their resources, and their capacity to address hazards. ​ Can also be defined as lack of power to be safe in times of disasters. ​ Vulnerability is situation-specific. ​ Vulnerability is not static and can evolve due to changes in: Governance and policies, Economic conditions, Urbanization and land use, Climate change and environmental degradation Vulnerability Factors Affecting Vulnerability The Asian Disaster Preparedness Center has categorized vulnerability into two, hazard-specific and setting specific. 1. Hazard-Specific - a characteristic which makes the element concerned susceptible to the forces or impacts of a hazard. -​ This refers to the susceptibility of a system, population, or asset to a specific type of hazard or threat. -​ The geophysical and locational attributes of the elements given are considered in this category. -​ This is primarily concerned with the nature and characteristics of the hazard itself, and how it directly affects people, structures, and systems. -​ The focus is on the nature of the hazard itself (its physical characteristics, intensity, and frequency) and its direct effects on the population. -​ Example: Catanduanes is vulnerable to typhoons. Surigao is vulnerable to tsunamis and storm surge. 2. Setting-Specific - a place or an area becomes susceptible to hazards according to their location or setting. -​ The main concern is whether it is located in a rural or urban setting. -​ This refers to how the specific context of the environment, infrastructure, economic conditions, social structures, and political framework in which a population exists affects their overall vulnerability. -​ Focuses on the conditions of the community that determine how well it can cope with, adapt to, and recover from that hazard. -​ It is about how the conditions of the place (e.g., poverty, lack of infrastructure, political instability) make the population more or less vulnerable to the same hazard. -​ Example: Manila, Philippines (Urban) and Bukidnon, Philippines (Rural) Key Differences: Hazard-Specific: The focus is on the nature of the hazard itself (its physical characteristics, intensity, and frequency) and its direct effects on the population. Vulnerability is linked to exposure to a particular hazard. Setting-Specific: The focus is on the social, economic, and environmental conditions of the community, which shape how vulnerable they are to any given hazard. Vulnerability is shaped by the context of the community. 2 Types of Vulnerability 1. Physical Vulnerability - pertains to potential damages a hazard can do to physical structures including buildings, houses, and transportation systems (roads, railways, airports, and seaports). 2. Social Vulnerability - is defined as “the people’s capacity to anticipate, cope with, resist and recover from impacts of natural hazards” (Wisher, et al. 2004). There are many factors affecting the social vulnerability of a certain community or group such as economic status, ethnicity, gender, age, religion, and disability. Remember: Presence of both physical and social vulnerabilities can increase the effect of the disaster on a community. LESSON 2 : Vulnerabilities of Sectors of Society to Disasters As a tropical country and due to its geographical location, the Philippines is exposed to different types of hazards, like typhoons. When a tropical cyclone hits a specific community, the degree or level of vulnerability varies due to some factors that might affect the capacity and resiliency of different sectors of society. The level of vulnerability to a typhoon of illegal settlements in the seaside area is higher than those settlements located in higher places and gated communities. Poverty is a significant factor in vulnerability and capacity, but it does not necessarily mean that low-income families are always vulnerable to hazards. Susceptibility to hazard increases due to lack of education and training on disaster preparedness. Communities living in rural areas do not have easy access to information available about disaster readiness and risk reduction. Factors that may affect different setors of society: 1.​ SOCIO-ECONOMIC FACTORS The following factors may affect different sectors of society: Socio-economic status or wealth plays a vital role on why some sectors of society are more vulnerable than others. Rich or developed countries do not suffer as much relative to developing nations when a natural hazard occurs. Disasters might affect the supply of food and other essential commodities and services of a country. The same is true to families whose houses are not compliant to the National Building Code of the Philippines (materials, structure, ventilation, sanitation, and others). When a strong earthquake hits their location, their houses are more likely to be affected or destroyed. While families that reside in structurally sound concrete homes or high-rise condominiums, have lesser vulnerability during earthquakes, fires, or typhoons. There are also families that have the budget to buy first aid kits and stock necessary supplies (food and clothing) that they might need during and after a disaster, while the others cannot even purchase food thrice a day because of their everyday financial struggle. Government and other non-governmental civic organizations education programs and activities lessen the impacts or effects of disasters. The quarterly National Simultaneous Earthquake Drill (NSED) of the Office of Civil Defense (OCD) together with other government agencies and local government units like the Bureau of Fire Protection, Municipal/City/Barangay Disaster Risk Reduction and Management Office, and other relevant agencies help improve the level of awareness and preparedness of communities when disaster happens. Government agencies also have the primary task of ensuring a safe and resilient environment and community. They are responsible for planning and creating measures to lessen the impact of disasters on the cities. The movement of people from one place to another is called migration. This shift can be due to different factors, and displacement also affects the level of vulnerability of people. Migrants, refugees, and internally-displaced persons (IDP) do not receive the same response and relief from the government. Typically these types of people suffer most when disaster strikes because of their unfamiliarity with their current place of settlement.  2.​ DEMOGRAPHIC FACTORS During the Zamboanga siege, more than two hundred thousand internally-displaced people of Zamboanga were forced to stay in unprepared evacuation sites. Tents were the primary form of shelter for these people. When a typhoon hit these evacuation sites, the majority of these tents were damaged and even destroyed. It created a broader and more extensive problem that the government had to address. In the case of migrants, due to their unfamiliarity when disaster strikes, they may be unaware of the places such as where to ask for help and whom to ask for help. There are instances when the host country prioritizes their citizens before they extend relief to migrants. Demographics Settlement patterns and population density that are both associated with urbanization increase vulnerability to disaster risk. Rapid urbanization comes with a ballooning population. It has increased the number of people exposed and vulnerable to disaster risk. Due to its rapidness, unplanned development and poor infrastructure pose a serious threat. Urbanization attracts people from surrounding areas making it more difficult for the government to provide adequate resources and training to increase capacity and prevent disasters. Rural and small communities also have high vulnerability because of lack of resources. Government budget for rural communities is smaller than for urban areas. Age of population or the number of young and seniors living in communities is also a prime factor in determining the level of vulnerability. These groups are more vulnerable because of their inability to respond and cope with disasters. They require more attention from the government and society during emergencies. In a typical evacuation scenario, the first to be evacuated are women, children, and the elderly. People who also suffer from illness are also vulnerable and need immediate attention during emergencies. Social groups such as the marginalized (groups excluded or underrepresented in planning and decision-making) are those discriminated against during the post-disaster rescue, relief operations, recovery, and rehabilitation efforts. The following are the most commonly identified marginalized or excluded groups in times of emergencies: pregnant women, racial or ethnic minority, mentally and physically challenged individuals, tourists , Migrants, prisoners These groups of people are not biologically excluded but separated through socially constructed barriers. For example, after a typhoon hit a coastal community, the pregnant women and the elderly were left in evacuation centers for care and medical assistance. During typhoon Haiyan “Yolanda” a jail breakout of the inmates was reported in Leyte Provincial Jail. This breakout was done to save their lives. LESSON 3 : Vulnerability of Certain Structures to Hazards Here are three primary concepts that one should know before directly discussing the vulnerability of physical structures. This concerns houses, buildings, roads, bridges, dams, seawalls, and other public and private infrastructures: 1. Engineered construction - code compliant -​ followed the process of securing a building permit, thus ensuring the compliance with safety standards that can withstand earthquakes or other similar hazards. -​ Example: Golden Golden Gate Bridge and Burj Khalifa 2. Non-engineered construction - designed by incompetent engineers and architects. -​ they do not follow the safety standards of building construction. 3. Owner-built buildings - mainly constructed by their respective owners with the guidance of a head-mason or master-carpenter who probably lack knowledge and competent skills on making earthquakeproof buildings. 2 Main Types of Vulnerability in physical structures 1.​ Structural Vulnerability - pertains to structural integrity or elements of a building and is composed of the following: a.​ Location: primarily dictates the type and degree of vulnerability of the structure b.​ Number of surrounding buildings: The vibration of neighboring buildings might affect its strength and durability especially if the surrounding buildings are older and weaker, much more if they are non-engineered ones. c.​ Number of stories: Vulnerability increases when height increases.  d.​ Shape: Complex shapes (e.g., L-shape, Y-shape, H-shape, etc.) increase the building’s vulnerability to damage and destruction during an earthquake. e.​ Symmetry: Symmetrical planned structures as well as in elevations (both directions) perform much better than an asymmetrical building during an earthquake. f.​ Age of building: While other buildings 50 years and above still stands today, there are also old buildings that pose hazards to occupants and surrounding houses or buildings. g.​ Typology: Materials used to build these structures also affect the degree of its vulnerability. h.​ Alteration: An original nine-story building that was altered and was added additional floor is more vulnerable to an earthquake because its structural frame was designed for only nine-stories. i.​ Maintenance - If owners poorly manage the building, eventually it will become more vulnerable because of the unseen deterioration of interior and structural frames. 2. Non-structural Vulnerability - pertains to other parts of a house or building that were not designed or planned with a structural engineer: ​ Walls, ceilings, light, fixtures, doors and frames, electrical equipment, mechanical equipment, plumbing , electrical installation Aside from these two main physical structures that are vulnerable to disaster risk, there are also critical facilities in a community that are vulnerable in times of emergencies. These facilities play important roles in rescue, relief, and rehabilitation: ​ Hospital, water supply facilities, electrical distribution facilities, telecommunication lines, transportation hubs such as airports, seaports, road, rails, and bridges, schools that serve as evacuation areas/center LESSON 4 : Elements Exposed to Hazards Exposure - can be described as the situation of communities including its people, residences, infrastructure, and economic resources that are located in areas that are hazard-prone (UNISDR, 2017). -​ If a typhoon with heavy rainfall hits a residential area, they may be affected by the flood. -​ Exposure varies from location and the presence of hazards in the area. -​ Example: The exposure of the communities around an active Mayon Volcano located in Legazpi, Albay in Bicol Region is different from those who live in the mountains of Mindanao. Overpopulation as well as urban development increase chances of spreading risk to people and assets. Developed cities become densely populated as more capital is being invested in these areas. More jobs are created as a result of urbanization and people living in rural areas migrate to cities to look for jobs. This scenario can make the effect of a disaster worse. NOTE: Urban development, previous disasters, economic opportunities, cultural and religious reasons are examples of exposure drivers. Elements Exposed to Hazards Effects of Different Hazards: Physical aspects refer to a location-specific context for humanenvironment interaction (Smithers and Smith, 1997) and the material world (e.g., built structures). Settlements of people to hazard-prone areas or landscapes because of their economic benefits and promises have made physical exposure of human beings and its establishments to hazards (UNISDR, 2004). Physical aspects of geography, location, and place; settlement patterns; and physical structures including infrastructure located in hazard-prone areas or with deficiencies in resistance or susceptibility to damage. ​ The 12 million plus population of Metro Manila are exposed to different hazards like floods, liquefaction, and the 7.2 magnitude earthquake popularly known as the Big One.  ​ Natural phenomena such as typhoons, earthquakes, volcano eruptions are natural events and are beyond the control of the human power. Such situations may directly or indirectly cause risk and hazards to people. Moreover, it is not only natural events that are causing harm to people. There are also other catastrophic events which are caused by specific elements exposed to potential hazards. Certain elements could be exposed to particular hazards or could be the possible hazard in itself based on the circumstance. The conduct of disaster risk assessment is an essential activity which can practically determine the different elements exposed to certain types of hazards. The vulnerability of such elements if not recognized and given action can be considered as an impending disaster. In this situation, we can say that without any knowledge on these elements such as housing infrastructures, material possessions, assets, as well as the people living in particular areas where there are particular hazards; all are exposed to a specific level of risk and vulnerability. Specific Types of Elements Exposed to Hazards An electrical fire is one of the most common disasters which happens in many populated places. In this instance, people, infrastructures and assets are the most common elements exposed to this particular hazard. ​ Electrical gadgets and appliances left unattended. There were many cases wherein electrical devices and gadgets have been the cause of fire. When overheating happens in densely populated areas where houses are made of light materials, it is more likely to create a disastrous situation. ​ Faulty electrical wirings. Most of the electrical fires happen because of defective wiring. In most cases, non-compliance to standards were the common reasons for the occurrence of electrical fires. ​ Faulty outlets and outdated appliances. Some fires started because of outdated or poorly maintained old appliances. ​ Light fixtures. Light bulbs are also subject to electrical fires. Lamps with too high or wrong wattage is one of the leading causes of electrical fires. ​ Extension cords. Overloaded extension cord is another primary cause of electrical fires. ​ Space heater. Some people with a high-level use of heaters are considered to be a contributing factor to causes of electrical fires. ​ Biological substances and chemicals. Many people are unknowingly exposed to substances that are hazardous to health which are usually in the wide range of chemical and biological agents which are used in household work activities or even in the workplace. Many of these substances are volatile and flammable which can start a fire (though not of electrical but of chemical or biological origin). Specific LESSON 5 : Vulnerabilities of Elements Exposed to Hazards Exposure and vulnerability are two different things. Two elements can be exposed in the same setting but have different levels of vulnerability. Types of Vulnerabilities of Elements Exposed to Hazards 1. Physical Vulnerability- refers to objects that are susceptible to hazards. This includes classifying the vulnerability of different elements such as houses, buildings, and infrastructure. Physical vulnerability of an area depends on how close hazards are to their location. 2. Social Vulnerability - encompasses identifying people’s capacity to cope with hazards, being able to form a structured organization, and creating an implementation of proper disaster risk reduction and management. 3. Environmental Vulnerability - describes the potential degradation of the surrounding landscapes including bodies of land and water, and biodiversity due to hazards. This vulnerability is of great concern because of the environment’s diverse role to the people and the community. 4. Economic Vulnerability - identifies the potential losses of resources of the people and the community. This is linked to other types of vulnerabilities. Economic losses are incurred when physical disasters occur. Destruction of houses, buildings, or infrastructures has a significant effect on the resources of a person, community, or business. NOTE: The four types of vulnerabilities are not mutually exclusive. They can be linked to one another. Hazards are difficult, if not impossible, to remove from a particular area. Exposure of elements is much easier to reduce. Reducing the vulnerabilities of different elements exposed to hazards can be done. Coping Mechanisms for Vulnerable Elements ​ Strengthen Physical Structures ​ Store Resources ​ Improve Communication and Awareness ​ Combine Local and Expert Knowledge LESSON 6 : Hazards, Exposure and Vulnerabilities Hazard is defined by the United Nations Office for Disaster Risk Reduction (UNDRR) [2 February 2017] as “a process, phenomenon or human activity that may cause loss of life, injury or other health impacts, property damage, social and economic disruption or environmental degradation”. There are three (3) main types of hazards; natural, anthropogenic, and socio-natural. Natural Hazards - These hazards are predominantly associated with natural processes and phenomena (UNISDR, 2017). These hazards are impossible to prevent. -​ Three Types of Natural Hazards: Geological and Geophysical Hazards, Biological Hazards, and Hydro-meteorological Hazards -​ Anthropogenic Hazards - These hazards are human-induced hazards, induced entirely or predominantly by human activities and choices (UNISDR, 2017). -​ Type: Technological Hazards - may arise directly as a result of the impacts of a natural hazard event (UNISDR, 2017). -​ EXAMPLES: Industrial Pollution, Nuclear radiation, and Toxic wastes Socio-natural Hazards - the combination of anthropogenic and natural factors such as environmental degradation and climate change (UNISDR, 2017). -​ can also happen when a natural hazard interacts with degraded environmental resources. -​ EXAMPLES: Flooding in Urban Areas and Droughts in Agricultural Area JESCAR MACARAEG CUTE (REAL) UNIT 3: Hazards Introduction: ​ Exposure - any element (people, property, or system) that is present in a hazard and is prone to potential loss. ​ Vulnerability - feature of a community that makes them prone and exposed to the negative impacts of hazard. ​ Exposure and vulnerability relate to hazard as the three are the risk factors underlying disasters. Basically, when combined, exposure, vulnerability, and hazard creates disaster risks. ​ Understanding hazards are essential in improving the quality of response to disaster risk reduction. ​ MITIGATION. Through understanding hazards, communities can build resilience and enhance their capacity to respond and recover from disasters, and this contributes to saving lives and resources by making informed decisions before crises occur. ​ A natural event or phenomena is a physical event that is natural in origin (geological, hydrometeorological or biological) ​ Vulnerability increases the susceptibility of a given community to the impact of a hazard. It is affected by physical, social, economic and environmental factors or processes. ​ Exposure is the degree or likelihood that a hazard will be experienced by elements at risk; it comes in varying degrees depending on the proximity of exposed elements to hazards and the magnitude of the hazard event. ​ A disaster happens when the impact of hazards on human lives and socio-economic activities is significant and extensive. ​ A catastrophe is bigger than a disaster. ​ Hierarchy: Hazard < Disaster < Catastrophe ​ The World Risk Index is calculated by Alliance Development Works and United Nations University Institute for Environment and Human Security. It calculates the natural disaster risks for 171 countries. ​ Climate is the average weather conditions of a place or regions of the Earth observed over a period of years. The weather conditions include temperature, wind velocity, and precipitation. ​ The Plate Tectonics Theory states that the lithosphere is made up of several plates that move either by floating on or gliding over the asthenosphere, and that seismic and tectonic activity occur at the plate boundaries. ​ Volcanoes that are located at the plate boundaries in the Pacific Ocean area form a ring, called the Pacific Ring of Fire. Lesson 1: Hazards A hazard is a natural event or a human activity that has the potential of causing loss of life, injury or other health impacts, property damage, social and economic disruption, or environmental degradation. -​ Hazards are future threats coming from different origins. -​ Hazards are situations or conditions that can cause harm to people or the environment. They can be natural, technological, or anthropogenic. -​ Hazards can be divided into different categories of hazard: physical, chemical, biological and environment. -​ A hazard is a potential threat, while a disaster is the actual event that causes harm. -​ Hazards can be natural or man-made, and disasters are always caused by hazards. Natural events - occur naturally; it may be biological, geological, or meteorological in origin Environmental degradation and technological hazards - results of human activities. When is a Hazard considered as One? When the natural event is close to or at the center of a populated area, that natural event is transformed into a hazard. Natural events such as volcanic eruptions, earthquakes, or floods will remain as natural events when they do not impact human lives or property. Population and economic development predict the likelihood of the hazard. A hazard is considered a hazard when: ​ It has the potential to cause harm. This means the hazard could lead to injury, illness, damage to property, or environmental damage. ​ There is a possibility of exposure: Someone or something could come into contact with the hazard. ​ There is a chance of harm occurring: The likelihood of harm might be small or large, but it exists. Why is a Hazard Significant? -​ Hazards are significant because they can cause harm to people, property, and the environment. They can also endanger people's safety and well-being. -​ Hazard completes the three elements of disaster risk. Hazard, exposure, and vulnerability increase the occurrence of disaster risk. Combining the three elements, the damage to life and property becomes significant. -​ Essentially, hazards are potential threats to human life and property. That threat is determined by demographics, urbanization, poverty, and environment. -​ A hazard can transform into a disaster depending on exposure and vulnerability. Underlying the three elements are human decisions and actions. Where to live, what to build, and what livelihoods to participate in, are questions and decisions that affect the levels of exposures to hazards. Living and health conditions, resources and skills define vulnerabilities. The frequency of hazardous events, therefore, greatly depends on socioeconomic conditions and activities. Lesson 2: Types of Hazard The understanding of hazards includes the knowledge of the what, where, when, why, and how we can help in reducing the impact of hazards on human lives, socio-economic activities, and the environment. ​ The United Nations International Strategy for Disaster Reduction (UNISDR) - now known as United Nations Office for Disaster Risk Reduction (UNDRR) - classifies hazards into two: natural and human-induced. ​ Hazards of natural origin can be categorized as geological, hydrometeorological, or biological, while the categories under human-induced or anthropogenic hazards are environmental degradation and technological. Natural Hazards ​ Geological hazards are natural events that originated from movements of the crust. This includes earthquakes, volcanic eruptions, tsunamis, and landslides. ○​ Geological hazards are caused by INTERNAL PROCESSES within the Earth, such as the movement of tectonic plates and the release of magma. ○​ The forces that act from the earth's interior towards the earth's surface are called internal processes or endogenic processes.  ​ Hydrometeorological Hazards - are hazards that originated from atmospheric conditions and composition. Cyclones and its associated hazards such as storm surges can either be called hydro- meteorological or atmospheric hazard. ○​ Hydrometeorological hazards (hydro-meteorological disasters) are of atmospheric, hydrological or oceanographic origin. ○​ Examples are tropical cyclones (also known as typhoons and hurricanes); floods, including flash floods; droughts; heatwaves and cold spells; and coastal storm surges. ​ Biological Hazards - originated from living organisms, usually in the form of harmful microorganisms that have potential to cause epidemics. ○​ Biological hazards include bacteria, viruses and parasites. ○​ They can pose a threat to human health when they are inhaled, eaten or come in contact with skin. ○​ They can cause illness such as food poisoning, tetanus, respiratory infections or parasite infection. ○​ Living organisms (humans, trees, animals, bacteria and insects). Human-induced Hazards or Anthropogenic Hazards - under human-induced or anthropogenic hazards are environmental degradation and technological. -​ But when there is an interaction between natural events and human activities, it is referred to as a quasi-natural hazard. -​ Many natural hazards may be influenced by human activities. An example would be a landslide due to a mining activity in the area. Drought can be classified as climatic because it results from long periods without precipitation. However, drought can be influenced by human activities that brought about climate changes. Another way to classify natural hazards is to group them into tectonic and climatic. ​ Tectonic hazards pertain to impacts of the earth movements. In this classification system, geological hazards are classified as tectonic and some hazards that may also be related to water (e.g. tsunamis, lahar flow, sand boils, geysers) are traced to their tectonic origins. ​ Climatic hazards refer to the impacts of weather conditions but there can be weather-related hazards that bring about geological hazards. For instance, a typhoon can induce a landslide in a deforested mountainous area. Hazards may be classified in several ways but they are always either due to natural processes or induced / influenced by human activities. Hazard risks are increasing due to the growing population, increased urbanization, and human-induced changes in the environment. The consequences of these hazards will have social, economic, and environmental impacts. The risks depend on the decisions and actions people take. Lesson 3: Impacts of Hazards on Exposed Elements There are other ways to describe hazards aside from their origins or types. Hazards are reported based on their characteristics, mainly on their levels of impact. Descriptions are quantified to measure their magnitude and intensity.  ​ Magnitude refers to the strength and power of an earthquake to which we can predict its potential destructive capacity. ​ Intensity measures the severity of an earthquake or the level of impact it caused in a specific area. - For typhoons or rainfall, color codes or numbers serve as warnings. Advisories also report the size and severity of the hazard. The onset of hazards, its duration, and frequency based on historical records are also utilized to describe and predict the occurrence of hazards. These measurements are useful in determining the levels of risks, potential damages, disruptions, and most importantly the level of responses to minimize the impact of hazards. - The levels of impact of hazards depend on its interaction with the physical, social, economic and environmental elements found in a given geographical location of people, property, and infrastructure. ​ Physical impacts of a Hazard include the destruction or damage to infrastructure such as facilities, transport systems, roads and bridges, communication systems, water supply systems, and energy supplies and power lines. Housing and tangible human assets belong to this impact. Mortality, human injuries, and health impacts are classified under this as well. ​ Socio-cultural impacts of a Hazard. Hazards can disrupt human and community activities. Populations like ethnic groups are displaced and are forced to migrate and adapt to a new culture and environment. This may cause loss of cultural identity and conflicts. All of these cause human stress. ​ Economic impacts of a Hazard. The disruption of economic activities will have a negative impact on investments and economic opportunities, production capacities, supply and flow of resources, and delivery of services and goods. This will lead to loss of livelihood and increased poverty. The latter will push people further towards a negative coping capacity to hazards and disasters. ​ Environmental impacts of Hazard. Hazards can change physical features of land and water forms. Tributaries can be permanently flooded, or coastlines can take a new shape or appearance. Land surfaces in both urban and mountainous areas can lose their permeability surfaces which bring flooding and landslides. Land subsidence is another consequence. Hazards can also increase the pressure on marginal lands, coastal, and low lying areas. ​ Biological impacts of a Hazard. A hazard or a disaster can cause another form of hazard to happen. An explosion of a nuclear reactor caused by an earthquake will increase radiation levels in the vicinity. Exposure to radiation causes chronic and permanent illnesses. Epidemics and the spread of viral or bacterial diseases also fall under this impact. Hazards have different impacts on people. Their vulnerabilities are determined by their skills, resources, their community organizations, and the government. The coping capacities of people are shaped by these factors. Disaster risk reduction programs should be built around these factors. JESCAR MACARAEG CUTE (REAL) UNIT 4: Earthquake Hazards Lesson 1: Ground shaking ​ An Earthquake occurs when large volumes of rock suddenly move along fractures in the Earth's crust, called faults. This happens because tectonic plates, which form the Earth's outer shell, get stuck due to their rough edges while they continue to move. ​ When the plates overcome the friction and separate, the stored energy is released as seismic waves. These waves travel through the Earth and radiate outward like ripples, causing the shaking felt on the surface. Two types of seismic waves: ​ Body waves - are seismic waves that travel through the interior of the earth. ○​ Primary (P) waves - are the first waves that reach the surface of the earth and make the ground shake. They move the ground back and forth along the direction they are traveling. The shaking is light or sometimes not felt. ○​ Secondary (S) waves - are body waves that vibrate perpendicular to their propagation direction, producing an up and down motion. They move slower but shake the ground more strongly than P waves. ​ Surface waves - are seismic waves that travel along the Earth's surface and cause the most damage during an earthquake. They move slower than body waves but produce stronger ground shaking. ○​ Love waves - are surface waves that have a horizontal motion perpendicular to the direction they are traveling. ○​ Rayleigh waves - shake the ground in a rotational manner with no transverse motion. -​ Ground shaking varies depending on (1) the type of seismic wave involved, whether moving the box vertically and laterally, (2) the duration and the frequency of the earthquake, like changing how long and how fast you shake the box. -​ The severity of an earthquake is measured based on the energy it releases, or its magnitude, and its effects on people and man-made structures, or what we call intensity. -​ Whether these are weak tremors or violent vibrations, ground shaking typically lasts for a few seconds to a minute. However, there are rare instances wherein shaking exceeds 60 seconds. -​ Frequency is the number of times a movement such as ground shaking is repeated within a certain amount of time. High frequency earthquakes affect small buildings more than the high rise ones. -​ The intensity of ground shaking is also influenced by the distance from the fault. Intuitively, you would expect to feel ground shaking more strongly if you were closer to the fault. This is true for most earthquakes, but you may also experience the same strength of shaking even if you were farther because of the physical properties of the ground that the structure was built on, and the structure itself. -​ When waves travel from hard (e.g. igneous rocks) to soft materials (e.g. limestone, sandstone, alluvium) and lose velocity, they must undergo an increase in amplitude to maintain the same  amount of energy. Hence, shaking is felt more strongly in areas with soft rock, where seismic waves move slower. -​ How a building is constructed can increase or decrease the damage from ground shaking as well. Numerous studies on earthquakes that have occurred in different parts of the world show that high mortality rates are a consequence of poorly constructed buildings -​ Ground shaking is the primary cause of earthquake damage to man-made structures. It causes buildings and other infrastructures to collapse which may result in injuries or casualties. In cases where it breaks water dams, flash floods may occur. -​ Fire is a secondary hazard if the shaking sufficiently damages electric and gas lines. -​ Ground shaking also triggers other earthquake hazards such as landslides and liquefaction. -​ It is not impossible to minimize the damage caused by ground shaking. Thorough geologic site investigation, stricter building code implementations, and earthquakeresistant construction are some ways of doing this. Knowing the characteristics of the ground you intend to build a structure on can help reduce potential ground shaking damage. You may opt to avoid constructing in an area if the underlying material amplifies ground shaking. -​ Building code is a set of rules that set standards on the construction of buildings. If properly implemented, it can ensure that buildings are constructed properly, can survive an earthquake with minimal damage, and therefore, not endanger the occupants. Lesson 2: Ground Rupture -​ It is the visible breaking and displacement of the Earth’s surface along the trace of a fault. Types of faults: ​ Strike-slip faults - are vertical or nearvertical faults that displace rock horizontally. ○​ Sinistral (left-lateral) Fault ○​ Dextral (right-lateral) Fault ​ Normal faults - are characterized by the downward movement of the hanging wall with respect to the footwall. ​ Reverse or thrust faults are faults which move the hanging wall up. Note: ​ Strike-slip faults cause lateral (dextral or sinistral) movement. ​ Dip-slip faults cause vertical (normal or reverse) movement. ​ Ground rupture can be a combination of lateral and vertical movements such as left-lateral normal, right lateral reverse, leftlateral reverse, right-lateral normal. Lesson 3: Liquefaction -​ There are cases wherein water rises from the ground as the ground shakes. -​ Sometimes, witnesses would describe the ground seemingly acting like a liquid during an earthquake. Those descriptions of earthquake impacts are associated with the phenomenon called liquefaction. -​ It occurs when the ground loses stiffness and behaves like liquid in response to earthquakes. -​ It occurs in saturated soils. Process of Liquefaction: ​ During an earthquake, the grains of the underlying material vibrate and undergo compaction, then sediments are compressed and fluids in the pore spaces are squeezed out. When the pore water pressure increases and becomes equal to the weight of the overlying material, liquefaction occurs. Factors of Liquefaction: Liquefaction is affected by different factors: ​ Duration ​ Intensity of the shaking ​ Proximity to the fault ​ Density of infrastructure in the area ​ Geology ​ Stronger, prolonged shaking produces a greater degree of liquefaction. -​ Liquefaction at depth can cause geysers of sand and water to shoot from the ground, a phenomenon called sand boils. Areas Affected by Liquefaction: ​ Research on earthquakes occurring in different areas by Leeder (1982) shows that liquefaction affects areas as far as hundreds of kilometers away from the epicenter. ​ Denser infrastructure or more buildings in a certain area (populated centers/areas). ​ Urban communities built with loosely-packed, saturated sediments. In the case of Metro Manila, liquefaction susceptibility maps have been prepared by PHIVOLCS to monitor potential liquefaction sites and to disseminate this information to the public. You can find these and other hazard maps on their website. Note: ​ In liquefaction, the ground is unable to support the structures on top of it, causing buildings to tilt and/or sink into the ground. ​ Liquefaction is affected by the duration and intensity of the shaking, proximity to the fault, density of structures on the surface; and the kind of materials underneath the surface. Leson 4: Earthquake-Induced Landslides How can earthquakes induce landslides? ​ Landslides sometimes occur during or after earthquakes. ​ Mass wasting, more commonly known as a landslide, is the downslope movement of rocks or sediments under the influence of gravity. ​ It is the process that follows weathering or the removal of rock or debris from their original source. ​ Landslides can be triggered by factors such as heavy or prolonged rain, oversteepened slopes, removal of vegetation, and earthquakes. ​ Vibrations from an earthquake and its aftershocks can displace significant amounts of rock or sediment. For an earthquake to induce landslides,the following are the factors that must be considered: ​ The strength of the earthquake - Keefer (1984) determined that the minimum magnitude required to trigger a landslide is 4.0. Aside from the earthquake, the landslide was also caused by intense, prolonged rainfall and creep. Creep is the gradual, almost imperceptible downward displacement of sloping rock or soil caused by buildup of significant strain. ​ The distance from the fault - Earthquake-induced landslides are more likely to occur in areas located at a certain distance from the fault. ​ Topography - Specific topographies have a greater likelihood of experiencing earthquake-induced landslides. These landslides typically occur in hilly and mountainous areas, especially in portions where the slope is cut to build roads and other man-made structures. Moderate to steep slopes promote the gravity-driven movement of rock and sediments. ​ Climate and the characteristics of the rock or soil - Extended periods of rainfall increase the moisture content of the soil/sediments on a slope, making these materials more susceptible to earthquake-induced failure. How soon a landslide occurs after an earthquake varies. It can be abrupt, giving you little time to prepare or flee. In some cases, there are warning signs you can watch out for: ​ cracks or bulges in the road or ground that weren’t there before ​ increased soil content in streams; leaning poles or walls ​ a rumbling sound that grows louder (indicating the approach of a landslide) ​ and unusual sounds such as cracking trees and colliding rocks. -​ To minimize earthquake-induced landslides, avoid building on steep slopes or near drainage ways. Know your home's foundation and proximity to faults for better evacuation planning. Stabilizing slopes or rock walls can also reduce landslide risk. -​ An earthquake-induced landslide susceptibility map is useful in determining vulnerable areas. Maps prepared by PHIVOLCS for the different regions of the Philippines are available on their website. These take into consideration two factors: critical acceleration and intensity. Two Earthquake Intensity Scale -​ The Earthquake Impact Scale is a tool used to quickly assess the potential impact of an earthquake on a specific region, including its effects on buildings, infrastructure, and people. -​ There are two earthquake intensity scales: the Modified Mercalli Intensity (MMI), and the PHIVOLCS Earthquake Intensity Scale (PEIS). Both scales do not have a mathematical basis; the levels are based on the effects of the earthquake observed. Higher numbers indicate greater structural damage or shaking felt. PEIS was developed specifically for the Philippine setting and takes into account the geography and geology of the country. Lesson 5: Tsunamis -​ It is a series of waves generated by large-scale displacements of water which are usually triggered by earthquakes or major submarine landslides. -​ The process by which waves change shape and height as they move from deep to shallow water is called wave shoaling. -​ Subduction zones are sites at convergent boundaries, where two or more tectonic plates collide, wherein one plate descends (subducts) beneath another. The downward movement of the subducting plate is driven by temperature. ​ Local tsunamis are from a nearby source. They are confined to coasts within 100 km or the distance they travel within less than an hour. ​ Regional tsunamis affect a wide geographical area, typically within 1,000 km or 1-3 hours of the wave travel time. -​ The damage and destruction from tsunamis depend on the degree of flooding, wave impact on structures, and erosion. -​ Tsunamis are detected by openocean buoys and tide gauges, which monitor and report any changes in sea level. -​ The following are some natural signs of an impending tsunami: -​ prolonged, severe ground shaking; -​ recording sea level or retreating ocean, exposing rocks, fish and corals in the ocean bottom; -​ loud ‘roaring’ similar to the sound of a freight train or aircraft; -​ and a huge incoming wall of water.  -​ One of the biggest Tsunami that hit the Philippines was the Moro Gulf Tsunami on August 12, 1976, near the Islands of Mindanao and Sulu. It was a deadly 8.1 magnitude earthquake. -​ The tallest tsunami in the world that was ever recorded is the Lituya Bay Tsunami in Alaska. According to a source, it was 1,720 feet (524 meters) and a 7.8-8.3 magnitude earthquake. Note: ​ Tsunamis usually originate from underwater earthquakes due to movements in subduction zones. ​ Tsunamis can be predicted but the damage and destruction it will cause cannot be precisely aniticipated. Unit Summary: ​ An earthquake is a phenomenon caused by the sudden and rapid movement of large volumes of rock along fractures on the surface of the earth called faults. ​ Ground rupture is the visible breaking and displacement of the Earth’s surface along the trace of a fault. ​ Liquefaction occurs when the ground loses stiffness and behaves like liquid in response to earthquakes. ​ Landslides can be triggered by factors such as heavy or prolonged rain, oversteepened slopes, removal of vegetation, and earthquakes. ​ A tsunami is a series of waves generated by large-scale displacements of water which are usually triggered by earthquakes or major submarine landslides. ​ JESCAR MACARAEG CUTE (REAL) UNIT 5: VOLCANIC HAZARDS Review -​ Volcanic eruptions in the Philippines have been recorded for centuries. Some were recorded for its catastrophic events while others were recorded for its mild activities. Take the case of Mt. Pinatubo eruption of 1991 for instance. Its eruption was one of the largest volcanic eruptions in recent history. Mt. Pinatubo spewed an unquantifiable amount of volcanic material that affected the Philippines socially, economically, and environmentally. Its effects were felt before the main eruption event and even years after that. -​ Plate tectonic theory explains that Earth's surface is made up of rigid tectonic plates that move, much like a surfboard on ocean waves. As these plates shift toward, away from, or alongside each other, they create various geological features, such as volcanoes. -​ The plates’ movements created the Pacific Ring of Fire, an area along the boundaries of the Pacific Ocean where a chain of volcanoes is located. This includes the Philippines which contains more than 50 active and potentially active volcanoes. Lesson 1: Lava Flows ​ Lava is a molten rock or magma that has reached the surface of the earth. ​ Lava flow occurs when magma contacts the surface of a volcano and erupts or overflows downhill from different volcanic openings. ​ Lava flows can be fluid or viscous depending on its composition, temperature, and gas content. ○​ Lava with low silica content, high temperature, and low gas content is considered more fluid. ○​ While lava with high silica content, low temperature, and has a high gas content is more viscous. ​ Lava is a molten material. It is not solid, liquid, nor gas, but a combination of all three. Types of Lava Flows: Lava flows come in two (2) types: ​ Pahoehoe (pronounced as Pa-hoy-hoy) is a type of lava flow with high fluidity and smooth, billowy, or ropy surfaces. ​ Aa (pronounced as Ah-ah) is a type of lava flow with high viscosity and rough, jagged, or clinkery surfaces. Note: As Pahoehoe lava cools, it transitions into an Aa. This is because of the slower and more viscous characteristics of the lava creating a blocky and jagged appearance. Aa does not necessarily transition from Pahoehoe. Negative Impacts of Lava Flows: Lava flows seldom threaten human life as most lava flows are as fast as a human’s normal walking pace. They can also be monitored quite easily compared to other volcanic hazards. Lava flows are still hazardous because they can crush and bury structures and livelihoods. They solidify over time making the areas buried by the lava useless. The solidification of lava also blocks roads and other pathways normally used by people. Lava flows also burn surroundings because of its intense heat. Flammable resources such as wood, plants, and houses can get caught on fire as lava flows along their path. Mitigating the Negative Effects of Lava Flows Like other volcanic hazards, lava flows cannot be stopped. Some can be controlled, however, to minimize its effects on people’s lives. Artificial barriers can be constructed to prevent and divert lava from flowing over a particular area. Water jets can also be used to cool and slow it down, eventually stopping its movement. Use of explosives can also alter the pathway and source of the lava flow. Examples of Volcanic Eruptions with Lava Flows and Response of Communities ​ Mt. Mayon, located in the Bicol Region, is one of the most active volcanoes in the Philippines. It has erupted several times on different occasions, spewing different types of material including lava. Lava flows from Mayon Volcano have been recorded since the early 17th century. Since then, no casualties caused by lava flow have been recorded. This is due to the ease of monitoring of the lava flow, and the fast information dissemination to the communities about the impending lava flow arriving in their area. ○​ Damages on properties and livelihoods, however, were imminent as lava flowed through the different towns surrounding the volcano. Early warning systems have been put in place by the Philippine government’s volcano observatory agency, the Philippine Institute of Volcanology and Seismology (PHIVOLCS), to minimize casualties and lessen the effects of these lava flows to the community. ​ Mount Kilauea in Hawaii is one of the most recognizable volcanoes in the world that produces lava flow. Hawaii is one of the known areas where lava flows constantly occur. Because the island of Hawaii is made out of active volcanoes, volcanic hazards have become part of their lives. Lesson 2: Volcanic Gases ​ Volcanoes release gases during and even in between eruptions. ​ Volcanic gases are composed of different materials depending on their location. Water vapor (H2O) and carbon dioxide (CO2) typically make up the bulk composition of volcanic gases, followed by sulfur dioxide (SO2). Other common volcanic gases include hydrogen chloride (HCl), and hydrogen fluoride (HF). ​ Volcano hazards are not mutually exclusive. Different volcano hazards can occur at the same time just like how volcanic gas can occur with or without lava flow. ○​ Mutually exclusive - a statistical term describing two or more events that cannot happen simultaneously. Negative impacts of Volcanic Gases Most volcanic gases are hazardous to people except for water vapor. Sulfur dioxide, when injected into the atmosphere, can form into sulfuric acid which is a component of acid rain. Acid rain does not only harm people but the environment as well. Acid rain can lessen water intake by plants, making them difficult to thrive. Direct contact with sulfur dioxide can also irritate the eyes, cause skin rash, and poison the respiratory system. Carbon dioxide is also dangerous, especially in high concentrations. It can cause asphyxiation without warning because of the gas’ odorless and colorless nature. Mitigating the Negative Effects of Volcanic Gas Mitigation - the action of reducing the severity, seriousness, or painfulness of something.  Unlike slow-moving lava flows that allow time for warnings, volcanic gases can be released suddenly with little notice. Their movement depends on wind direction rather than the land’s shape, making them harder to predict. Volcano observatories monitor gas levels, and people nearby are advised to wear masks or evacuate when hazardous gases are detected. Examples of Volcanic Gases and their Impacts ​ One of the most notable disasters that occurred because of volcanic gases was in 1986 in Lake Nyos, Central Africa. Lake Nyos is a crater lake formed on the top of an old volcano. Underneath the lake was a large pocket of carbon dioxide gas waiting to be unleashed. ○​ In August 1986, an eruption of gas took place underneath Lake Nyos spewing large amounts of carbon dioxide into the air. Residents saw this eruption, but they were not aware of the hazards it would cause because of the odorless and colorless nature of the gas. ○​ The dense carbon dioxide gas rushed down towards the northern valleys near the lake and suffocated almost two thousand people. Since then, the stretch has been mitigated by putting a degassing pipe to safely release the gas pressure underneath the lake and prevent future casualties. ​ There is an active volcano named Mount Ijen located in Java, Indonesia that releases high amounts of sulfur-rich volcanic gases. The locals are mining the area near the crater of the volcano for its high sulfur concentration. It is also well known to tourists because the volcano produces blue flames when sulfur from its lava combusts when in contact with the air. ○​ Locals and tourists hike here every day even if they are exposed to high amounts of volcanic gases. Short exposure to these gases does not have a lasting effect. However, the sulfur miners around the area have had different health problems such as poisoned lungs, irritated eyes, and teeth dissolution. Lesson 3: Pyroclastic Flows Volcanic eruptions can come with pyroclastic flows. What are pyroclastic flows and why is it hazardous to people? ​ Pyroclastic Flows are hot, dry, turbulent mass mixtures of different pyroclastic materials and gases that move downwards along the slope of a volcano at a speed that can go up to several hundred meters per second. ​ Pyroclastic materials, also known as tephra, is a collective term for volcanic fragments that have been ejected out of a volcano which vary in sizes from ash to boulders. Pyroclastic flows are composed of two parts: ​ Basal flow of coarse pyroclastic materials ​ Turbulent ash clouds riding over the basal flow. -​ When the turbulent ash cloud separates from the main pyroclastic flow, they are separately called the pyroclastic surge. Pyroclastic surges have lower density and are more mobile than pyroclastic flows because of their higher ratio of gas to tephra. NOTE: Pyroclastic flows are different from pyroclastic surges. -​ Pyroclastic flows are denser and follow the topography of the area. -​ Pyroclastic surges are less dense and less predictable because they can move in any direction other than the topography of the area. Types of Pyroclastic Flow: ​ Soufrière type - forms from the collapse of a high vertical column coming from a highly explosive eruption. When the force of gravity overcomes the momentum of the upward thrust of the eruption, the pyroclastic materials begin to fall creating a pyroclastic flow along the sides of the volcano. ​ Pelée type - occurs when a highly viscous lava dome blocks the opening of a volcano, building pressure until it can no longer be contained and explodes to one side of the volcano without forming a high eruption column. ​ Merapi type - occurs when a lava dome grows too steep over a volcanic crater which then falls due to gravitational force. ​ ​ Negative Impacts and Mitigation of Pyroclastic Flows Pyroclastic flows are one of the most dangerous volcanic hazards due to their high temperature, speed, and mobility. They can destroy structures, burn forests and buildings, and make areas uninhabitable for decades. The impact can crush and carry away large objects, while the heat can incinerate anything in its path. These flows can also lead to lahars when mixed with water. Since pyroclastic flows cannot be stopped or easily predicted, the only way to mitigate their effects is through early warning systems and evacuation before an eruption. Examples of volcanic eruption with lava flows and response of communities ​ One of the five greatest eruptions of the 20th century was the Mt. Pinatubo eruption. For the first time in roughly 500 years, Mt. Pinatubo erupted on June 9, 1991 and continued to erupt weeks after. It had the most explosive eruption on June 12, and 15 wherein unquantifiable amounts of volcanic material spewed out to the atmosphere as high as 30 kilometers and resulted in 36 hours without daylight in the surrounding area. The resulting eruption created a disastrous pyroclastic flow that traveled as far as 16 kilometers from the volcanic vent. ○​ About 20,000 indigenous people and more than a million lowlanders surrounding the volcano were directly affected. As a result of the unprecedented eruption, about 200 to 300 people died. This number is comparatively small relative to the number of people affected, considering the violence caused by the explosions. The minimal casualties was a result of the early warning system and evacuation enforced by the government within the area. Public information dissemination on the risk of eruption prior and during the early warning also helped in the cooperation and response of the affected people. Lesson 4: Ballistic Projectile and Tephra Falls - Ballistic and tephra flows are volcanic hazards that can reach long distances and cause harm to people. Tephras ​ Tephras are fragments of volcanic material that are ejected into the atmosphere from the eruption of a volcano. They are differentiated based on the size of the ejected fragment. They can be classified as ash, if it is less than 2mm, lapilli if it is 2-64mm, or blocks and bombs if they are greater than 64 mm in size. Ballistic Projectiles ​ Tephras ejected into the atmosphere will fall back into the earth’s surface. Large tephras that leave the volcanic vent with force and trajectory are called ballistic projectiles. These can have speeds of up to hundreds of meters per second and affect areas that are usually within the five-kilometer radius of the volcanic vent. Tephra Falls ​ Tephra falls occur as a result of tephra being spewed out by a volcano initially hovering and riding over the prevailing wind direction before eventually falling into the earth’s surface. They can hang in the atmosphere for long periods of time before falling, especially the ash particles that can be carried even up to thousands of kilometers. ​ Tephra fall deposits typically become thinner and finer as tephra goes farther from the volcanic eruption source. Tephra falls are also interchanged with ash falls because notable tephra falls are typically made up of ash since tephra, that is greater than a millimeter in size, typically falls thirty minutes after. NOTE: ​ The distribution of tephra falls is dependent on the prevailing wind direction while ballistic projectiles are nominally affected by wind direction. ​ Blocks and bombs are categorized into one because they have similar size categories. However, blocks are angular in shape while bombs are rounded. Negative Impacts of Tephra Falls and Ballistic Projectiles Tephra falls have the widest range of effects amongst all other volcano hazards. They can spread over a wide range of areas depending on how large the volcanic eruption is and how the prevailing winds move them. Ballistic projectiles, on the other hand, have effects that are in relative proximity to the volcanic source. This is because the projectiles are too heavy to be carried by prevailing winds. Their movement is mainly due to the initial force of the eruption of the volcano. Tephra falls and ballistic projectiles can destroy properties and endanger lives because of the force of impact as they fall into the Earth’s surface. Fragment size decreases as you move farther from the source which lessens the effect of impact hazard. Heavy tephra accumulation can collapse roofs, damage infrastructure, and harm agriculture, especially when mixed with water. It can also block drainage systems and release harmful gases. Examples of Impacts of Tephra Falls and Ballistic Projectiles ​ Iceland’s volcano, Eyjafjallajökull, that erupted in 2010, spewed ash into the atmosphere. This was a minor eruption compared to its other previous activities, but the massive amounts of ash it released resulted in the disruptions of traffic in large parts of Europe. The effect lasted for weeks as thousands of commercial flights were canceled causing hundreds of thousands of travelers to be stranded, and millions of dollars lost by different countries due to its economic effects. Lesson 5: Lahar Lahar ​ Lahar is an Indonesian term for mudflow that has been globally used as a term for a specific type of mudflow. ​ Lahar is created when tephras mix with water and form a slurry. ​ It flows along the slopes of a topography. ​ As they move downhill, lahar incorporates other materials along its path which can result in its volume growing more than ten times its initial size. ​ Lahar can form during the eruption event, called the primary lahar, or years after deposition of tephra called the secondary lahar. Primary Lahars ​ Primary lahars form when pyroclastic flows interact with bodies of water like streams and rivers, absorbing water as they move downhill. ​ Crater lake volcanoes can also generate primary lahars when eruptions cause lake water to mix with volcanic material and flow down the rupture site. ​ A specific type of primary lahar, known as Jokulhlaups or glacier bursts, occurs in Iceland and the Andes. These form when volcanic activity melts glaciers, combining the meltwater with volcanic materials and frozen particles to create powerful floods. Secondary Lahars ​ Secondary lahar can form after an eruption event. ​ Secondary lahar flows are generated when rain falls on unconsolidated tephra and mobilizes them downslope collecting more tephra as it progresses downward. ​ Mass failure or overtopping of dams formed by lava flows, lahar, pyroclastic flows, or crater rims can also cause secondary lahars. Note: ​ Lahar is a destructive volcanic mudflow composed of ash, rock, and water, originating from volcanic activity and rapidly flowing down slopes. ​ Lahars can form regardless of volcanic eruptions, triggered by heavy rainfall, glacier melting, or earthquakes, rapidly moving volcanic debris downslope. Negative Impacts of Lahars Lahar flows have destroyed cities and killed countless lives in the past decades. Their destructive nature can be attributed to their speed of flow, the extent of reach, composition, and difficulty of prediction. Lahar can travel quickly especially on steep slopes where its speed can reach more than 20 km/h. Its speed decreases as it flows into gentler low-lying areas. The force of impact from lahar, which contains varying materials of different sizes, can destroy virtually anything in its path. The reach of lahar flows defines their hazard. Some can reach up to more than 50 km from their source when confined to narrow pathways. Lahar is hyperconcentrated nearer its source.This means that it has a lot more material to water ratio, which decreases as lahar flows farther away from the source. Hyperconcentrated lahar destroys structures and agriculture through erosion. The diluted lahar, usually found farther from the source, can dry out and become as hard as concrete which becomes dangerous when it fills and buries an urbanized or agricultural area. A freshly deposited lahar can also act like quicksand that hampers immediate search and rescue efforts. Mitigating the Negative Impacts of Lahar Four basic risk reduction strategies: ​ Hazard avoidance - a complete ban of development in a lahar prone area, is the most effective way to reduce risk. ​ Hazard modification - this is accomplished by engineering structures to protect the affected area by diverting or blocking lahars, or weakening, or preventing lahar flows altogether. ​ Hazard warnings - this can help in disseminating information to the community of an impending lahar flow before it reaches and affects the community. ​ Hazard response and recovery planning - this focuses on the response to the lahar hazard after it has occurred. This strategy plans on the rescue of those affected by the hazard, how they will be taken care of, and the identification of long-term plans for the affected community. Examples of impacts of Tephra Falls and Ballistic Projectiles The 1991 Mt. Pinatubo eruption, combined with Typhoon Diding’s heavy rainfall, triggered lahars that flowed rapidly, burying everything in their path. These destructive flows persisted for years, causing deaths, infrastructure damage, and economic setbacks. Lahars followed river systems, threatening populated areas, but hazard warnings helped minimize casualties. Recovery efforts focused on resettlement, livelihood restoration, and infrastructure repairs. The severe impacts led to a more comprehensive risk reduction program to mitigate future hazards in surrounding communities.