Unit 15 GEOS

1. What is an earthquake?

  • Is a term used to describe both sudden slip on a fault, and the resulting ground shaking and radiated seismic energy caused by the slip

2.What effects or hazards may be produced by an earthquake?

  • Earthquake hazard is anything associated with an earthquake that may affect the normal activities of people. This includes surface faulting, ground shaking, landslides, liquefaction, tectonic deformation and tsunami.

3.Where are most Latin America earthquakes located? Why?

  • Circum-pacific “Ring of Earthquakes”

4.What is the interseismic period, what happens during this and how long does it last?

  • The long buildup phase between earthquakes.

  • Plates continue to converge, but are locked at the fault. This causes uplift and horizontal compression in the overriding plate.

  • Decades to centuries (10s–100s of years)

5. What is the coseismic period, what happens during this and how long does it last?

  • What it is: The brief rupture phase during an earthquake.

  • What happens: The fault breaks, releasing stored stress. This causes subsidence, horizontal extension, and may trigger tsunamis.

  • Duration: Seconds to minutes

6. What is an earthquake epicenter?

  • Is the point on the earth’s surface vertically above the hypocenter(or focus)

7. What is an earthquake hypocenter?

  • Is the location in Earth’s interior that ruptures

8. What is an earthquake focus?

  • same as hypocenter 

9. What is a earthquake magnitude?

  • Is a number that characterizes the energy released by an earthquake

10. What was the deadliest earthquake in Latin America?

  • Haiti, January 12, 2010

  • Magnitude: 7.0

  • Impact: 316,000 dead, 300,000 injured, 1.3 million displaced

11. What was the strongest earthquake in Latin America?

  • Great Chilean Earthquake, Chile; 1960; 9.5

12. What are Flat Slab segments and how are these related to Latin American earthquakes?

  • What they are: Subduction zones where the oceanic plate dives beneath the continent at a shallow angle.

  • Why they matter: They cause greater plate coupling, allowing more stress to build up — leading to larger, more destructive earthquakes.

  • Latin America: Found in Peru, Central Chile, and Bolivia

13. What is a tsunami and how do these form? Can any earthquake cause a tsunami? If not, what conditions are needed?

  • Definition: A series of large ocean waves triggered by sudden seafloor displacement.

  • How they form: Usually from underwater earthquakes at subduction zones where the seafloor is uplifted.

  • Not all earthquakes cause tsunamis. Conditions needed:Underwater location

  • Vertical displacement of the seafloor

  • Magnitude typically ≥ 7.0