Natural Hazards and Disasters Earth Science Presentation PDF

Natural Hazards and Disasters Objectives: 1. Describe the various hazards that may happen in the event of Geologic, Hydrometeorological and Marine coastal hazards. 2. Identify areas in your community prone to earthquake, landslide, flood,etc. 3. Cit...

Natural Hazards and Disasters Objectives: 1. Describe the various hazards that may happen in the event of Geologic, Hydrometeorological and Marine coastal hazards. 2. Identify areas in your community prone to earthquake, landslide, flood,etc. 3. Cite ways to prevent or mitigate the impact of land development, waste disposal, and construction of structures on control coastal processes.  Natural Hazards A natural hazard is the threat of an event that will likely have a negative impact.  Natural Disasters A natural disaster is the negative impact that effects the communities after a natural hazard. Types of Hazards Typhoons Earthquakes Flood Volcanic Eruptions Landslides Fires  Categories Geophysical Hydrological Meteorological Climatological Earthquakes Flooding Heat Waves Drought Volcanic Activity Landslides Cold Waves Wildfire Tsunamis Hurricanes Avalanche Hails Winter Storms Lightning Winds Tornados  EARTHQUAKE Earthquake- refers to the shaking of the ground due to the movement of rocks along faults(rock fracture). It is formed when there is a failure of rock mass to hold the accumulated elastic strain energy. - During an earthquake, the elastic energy is released sending out vibrations (seismic waves) that travel throughout the earth.  earthquake hazards Ground shaking –Disrupting up-down and sideways motion in an earthquake event that can cause physical damages. Ground rupture or surface faulting –Creation of new fractures or renewed movement along old fractures Liquefaction –Transformation of cohesion-less sand from solid to liquid state -the soil loosens and decreases the ability to support structures that are resting upon it. Tsunami –Huge sea waves induce by massive underwater disturbances by offshore earthquakes, underwater eruptions and landslides Landslides –Slope failure induced during ground shaking LIQUEFACTION LANDSLIDE  GROUND SHAKING OR TSUNAMI RUPTURE DOST FAULT FINDER volcanic eruptions Volcanic eruption is an activity where magma is released to the earth’s surface. Magma- a mobile rock material containing hot liquid about 800- 1000oC with or without suspended solids and dissolved gases. FACTORS IN MAGMA GENERATION 1. Temperature Rocks and minerals lose their stability upon encountering very high temperatures leading to partial melting 2. Pressures 3. Composition of magma 4. Presence of volatiles - volatiles such as water vapor, carbon dioxide, sulfur dioxide, chlorine, nitrogen lowers the melting temperature  volcanic eruptions ERUPTIVE BEHAVIOR OF VOLCANOES: Magma silicate melts and behave as fluids, therefore affected by viscosity (resistance to flow) Higher viscosity-”violent” eruptions Lower viscosity- ”quiet” eruptions HAZARDS CAUSED BY VOLCANIC ERUPTIONS A. Lahar and Floods A lahar (or mudflow) is a flowing slurry of volcanic debris and water that originates on a volcano. The eruption of a snow covered volcano can melt enough snow to cause a lahar. B. Poisonous gases - are released by volcanoes. These gases can be lethal to people, animals and plants. C. Can trigger a tsunami D. Pyroclastic flows LANDSLIDES GHAGJ  hydrometeorological phenomena 1. Monsoons- is a seasonal change in the direction of the prevailing, or strongest winds of a region. Monsoons always blow from cold to warm regions and often associated with the Indian ocean. 2. Tropical cyclones- are severe weather patterns, circulating around a low-pressure area. 3. Thunderstorms and Tornado Tropical cyclones are cyclones that are formed over warm oceans. The cyclones that form over the Pacific or Indian ocean are called Typhoons The cyclones that form over the Atlantic ocean are called Hurricane.  TYPHOON Powerful storms A low-pressure storm with winds swirling around the center Commonly occur in Southeast Asia  STORM SURGE 1. It is an 8-160 km wide dome of water that sweeps over the coastline during landfall. 2. Strong onshore winds and relatively low air pressure are responsible for a storm surge  Minimizing the Effect Engineers have worked hard to create technologies to help minimize the potential negative effect that comes with natural hazards.  The National Weather Service In the Philippines, the NDRRMC provides forecasts and alerts to protect communities from flood and earthquakes via wireless emergency alerts on android.  Technologies Avalanche Seismometers Water Gauges Doppler Radar Mortars Avalanche Mortars Seismometers are Water Gauges are Doppler Radars send are an explosive used to measure used to mark the out radio waves and device that are used earthquakes by water height and can are used to monitor to create small detecting vibrations single a need for storms that can avalanches so that in the Earth's surface. evacuation of include snow is not able to This helps to predict communities If the thunderstorms, hail build up to the point when earthquakes level reaches above a and tornados. of a catastrophic one. may occur. certain spot.  Engineering Engineering helps create solutions to help mitigate effects of Natural Hazards. From the technologies created to the ways in which homes are built engineers play an important role in helping protect communities.  Preparedness It is important that you are prepared for potential disasters depending on your location. Having an emergency supply kit and an emergency plan are two basic steps to be prepared!