Understanding Natural Hazards and Their Impact

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Questions and Answers

What primarily causes tectonic earthquakes?

Movement of tectonic plates (correct)

Human activities triggering landslides

Magma movement within the Earth's crust

The collapse of underground voids

Which effect is NOT typically associated with earthquakes?

Surface rupture

Ground shaking

Liquefaction

Saltwater intrusion (correct)

What factors contribute to the occurrence of volcanic earthquakes?

Rapid surface rupture

Movement of magma within the Earth's crust (correct)

Underground mining activities

Seismic waves caused by tectonic shifts

Which of the following is NOT a type of earthquake based on its cause?

Hydrometeorological earthquakes Signup and view all the answers

Which human activity is known to trigger landslides?

Overgrazing of land Signup and view all the answers

What is a common effect of both earthquakes and volcanic eruptions?

Significant damage to infrastructure Signup and view all the answers

What occurs during collapse earthquakes?

Collapses of caves or mines Signup and view all the answers

Which geographical phenomenon is typically related to tectonic earthquakes?

Landslides Signup and view all the answers

What effects do monsoons typically have on the weather?

They result in heavy rainfall and humid weather during the Habagat. Signup and view all the answers

What are some approaches to mitigate the effects of coastal erosion?

Planting mangroves and regulating groundwater use. Signup and view all the answers

Which statement accurately describes tornadoes?

They can cause severe damage with winds over 300 kph. Signup and view all the answers

What is a common consequence of saltwater intrusion?

Disruption of coastal communities and water supplies. Signup and view all the answers

Which practice is recommended to prepare for hydrometeorological hazards?

Prepare an emergency kit and plan with family. Signup and view all the answers

What is one of the main effects of subsidence on infrastructure?

Leads to increased flood risk Signup and view all the answers

How does liquefaction affect buildings during an earthquake?

Leads to tilting or sinking Signup and view all the answers

What triggers a tsunami?

Underwater earthquakes Signup and view all the answers

What is tephra?

Solid material ejected during a volcanic eruption Signup and view all the answers

What can lahars primarily cause?

Mudflows burying communities Signup and view all the answers

Which volcanic product is likely to disrupt air travel?

Tephra Signup and view all the answers

What is a potential factor that can trigger a lahar?

Heavy rainfall or melting snow Signup and view all the answers

What is one consequence of ashfall from tephra?

Contaminates water supplies Signup and view all the answers

What is a significant consequence of surface rupture during an earthquake?

It can sever utilities like water and gas lines. Signup and view all the answers

Which of the following is a characteristic of human-induced earthquakes?

They are linked to activities like mining and fracking. Signup and view all the answers

What factor influences the intensity of ground shaking during an earthquake?

The earthquake's magnitude and distance from the epicenter. Signup and view all the answers

Which earthquake outcome is described as the sinking or settling of the ground surface?

Subsidence. Signup and view all the answers

What can be a potential impact of ground shaking on structures?

It can lead to structural collapse. Signup and view all the answers

What is typically visible on the Earth's surface as a result of surface rupture?

Cracks and displacements. Signup and view all the answers

What is an essential practice to minimize damage from ground shaking?

Following building codes designed to withstand shaking. Signup and view all the answers

Which earthquake is possibly linked to geothermal energy extraction?

The 2017 Leyte earthquake. Signup and view all the answers

What are the primary dangers associated with pyroclastic flows?

Fast-moving currents of hot gas and volcanic matter Signup and view all the answers

Which volcanic hazard can create new landforms?

Lava flows Signup and view all the answers

What is one major cause of landslides?

Groundwater changes Signup and view all the answers

How can early warning systems help mitigate the effects of pyroclastic flows?

By monitoring volcanic activity and providing alerts Signup and view all the answers

Which of the following strategies can help in planning for earthquake hazards?

Using hazard maps Signup and view all the answers

What should be included in an emergency kit for coping with earthquake hazards?

Non-perishable food and water Signup and view all the answers

What is a recommended way to prevent landslides?

Building retaining walls Signup and view all the answers

What element is crucial for the formation of tropical cyclones?

Warm tropical oceans Signup and view all the answers

Study Notes

Introduction to Natural Hazards

Natural hazards are processes that can cause property damage, injuries, or fatalities.
Classified into geological (earthquakes, volcanic eruptions, landslides), hydrometeorological (tropical cyclones, floods), and coastal hazards (erosion, saltwater intrusion).
Understanding these hazards aids in preparation and mitigation strategies.

Earthquakes: Causes and Effects

Earthquakes result from tectonic plate movements; impacts include surface rupture, ground shaking, subsidence, liquefaction, and tsunamis.
Types of earthquakes:
- Tectonic Earthquakes: Most common, e.g., the 1990 Luzon earthquake linked to the Digdig Fault.
- Volcanic Earthquakes: Triggered by magma movement, e.g., the 1991 Mount Pinatubo eruption.
- Collapse Earthquakes: Result from underground voids, e.g., the 2012 Negros Oriental earthquake.
- Human-Induced Earthquakes: Linked to activities like mining and fracking, e.g., the 2017 Leyte earthquake.

Earthquake Outcomes

Surface Rupture: Ground breaks along fault lines causing physical damage; illustrated by the 1906 San Francisco earthquake.
Ground Shaking: Seismic waves causing collapses, especially in poorly constructed buildings; notable example is the 1994 Northridge earthquake.
Subsidence: Ground settling from structures or underground voids; significant in the 2011 Christchurch earthquake.
Liquefaction: Saturated soils losing strength during shaking, causing buildings to sink; seen in the 1964 Niigata earthquake.
Tsunami: Generated by underwater earthquakes, capable of extensive flooding; e.g., the 2004 Indian Ocean tsunami.

Volcanic Eruptions: Causes and Effects

Occur when magma surfaces, creating hazards like tephra, lahars, pyroclastic flows, and lava flows.
Tephra: Solid material from eruptions affecting air quality and agriculture; significant ashfall noted during the 1980 Mount St. Helens eruption.
Lahar: Rapid mudflows of volcanic debris, e.g., the 1985 Nevado del Ruiz eruption.
Pyroclastic Flow: Fast-moving and extremely hot; e.g., the 1902 eruption of Mount Pelée.
Lava Flow: Slow-moving molten rock, destructive to infrastructure; observed in the 2018 Kilauea eruption.

Landslides: Causes and Effects

Involves movement of rock or soil due to triggers like erosion, groundwater shifts, or seismic activity.
Human activities such as deforestation can exacerbate landslide risks.
Identifying hazardous areas through maps aids in disaster planning and management.

Coping with Geological Hazards

For earthquakes: practice drills, prepare emergency kits, secure household items.
For volcanic eruptions: plan evacuation routes, stay updated on volcanic activities, use protective gear during ashfall.
For landslides: avoid building near slopes, use vegetation for erosion control, construct supportive structures.

Hydrometeorological Hazards

Tropical Cyclones: Characterized by heat, low pressure, and heavy rains, leading to severe weather impacts.
Monsoons: Seasonal winds causing heavy rainfall; distinct patterns in the Amihan (cool) and Habagat (wet) seasons.
Tornadoes and Waterspouts: Violent winds causing severe destruction; capable of rapid formation and high wind speeds.

Coastal Hazards

Coastal Erosion: Sediment movement caused by natural forces; leads to loss of coastal land and infrastructure.
Submersion: Coastal areas submerging from rising sea levels; disrupts communities and ecosystems.
Saltwater Intrusion: Seawater encroaching freshwater aquifers; threatens drinking water supplies.

Mitigation Strategies for Coastal Hazards

Avoiding coastal construction, utilizing beach nourishment, and protecting shorelines with vegetation and engineered structures.

Conclusion

Awareness and preparedness are vital for combating natural hazards.
Proactive measures and community planning can significantly reduce risk and impact.

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Description

This quiz explores the concept of natural hazards and their potential impact on society. It covers various types of hazards, including geological events like earthquakes and volcanic eruptions, and their associated effects on life and property. The goal is to enhance understanding and preparedness for these natural threats.