tectonic hazards

• What happens at constructive margins?

  Magma forces its way to the surface
• What type of volcanoes are formed at constructive margins?

  Broad and flat shield volcanoes
• What causes mild earthquakes at constructive margins?

  Breaking of the crust by magma
• What occurs at destructive margins?

  Dense oceanic plate is subducted
• What type of magma is created at destructive margins?

  Sticky, gas-rich magma
• What type of volcanoes result from destructive margins?

  Steep-sided composite volcanoes
• What geological feature forms where two continental plates meet?

  Fold mountains
• What is the result of powerful earthquakes at continental plate boundaries?

  They can be triggered
• What happens at conservative margins?

  Two plates move past each other
• Why do earthquakes occur at conservative margins?

  Friction builds stresses that trigger earthquakes
• What was the cause of the Nepal earthquake?

  Indo-Australian plate colliding with Eurasian plate
• What was the magnitude of the Nepal earthquake?

  7.9
• What was the focus depth of the Nepal earthquake?

  15 km
• What were the primary effects of the Nepal earthquake?

  9000 killed, 20,000 injured, 3 million homeless
• What infrastructure was affected by the Nepal earthquake?

  Power, water, sanitation, and communications
• What was the estimated damage cost of the Nepal earthquake?

  $5 billion
• What were some secondary effects of the Nepal earthquake?

  Communities cut off by landslides and avalanches
• How many people were killed by avalanches on Mount Everest due to the Nepal earthquake?

  19 people
• What happened in the Langtang region after the Nepal earthquake?

  250 people went missing
• Why do people live at risk from tectonic hazards?

  Some regions are densely populated
• What are some reasons people continue to live in tectonic hazard areas?

  Earthquake-resistant buildings and rich soils
• What are the four management strategies for reducing risks from tectonic hazards?

  • Monitoring
  • Prediction
  • Protection
  • Planning
• What monitoring techniques are used for volcanoes?

  • Seismometers for microquakes
  • Tiltmeters for ground deformation
  • Instruments for gas emissions
• What monitoring techniques are used for earthquakes?

  • Seismometers to monitor earthquakes
  • Tsunami monitoring systems with floating buoys
• How does monitoring help in predicting volcanic eruptions?

  Allows accurate prediction and effective evacuation
• Why is accurate prediction of earthquakes difficult?

  Lack of clear warning signs
• What is a method of protection against volcanic eruptions?

  Earth embankments to divert lava flows
• What is the best way to protect against earthquakes?

  Earthquake-resistant engineering of buildings
• How is hazard mapping used for volcanic risks?

  Identifies areas for controlled development
• What are shakemaps used for in earthquake planning?

  Identify lower-risk areas for buildings