Earth Science Frequently Asked Questions

Questions

Alaska

• How many earthquakes does Alaska experience in 1 year?
• Do all of Alaska’s earthquake occur on mapped faults?
• What parts of Alaska have the highest seismic hazards?
• Why are there so many earthquakes in Alaska that don’t occur at plate boundaries?
• Can a tsunami generated in Alaska affect Hawai’i?

Basin and Range

• How much does the Basin and Range Province expand each year?
• How does the thickness of the tectonics plate under the Basin and Range Province compare to other parts of the world?
• Why are there a large number of mines in the Basin and Range Province?
• Will any new volcanoes form in this region?
• How do volcanoes form in the middle of a tectonic plate?
• What role does the thickness of the tectonic plate in the Basin and Range Province play in the formation of volcanoes?
• Are any Basin and Range volcanoes active today?
• What types of volcanoes are found in the Basin and Range Province?
• What is the maximum depth of an earthquake in the Basin and Range Province?
• Why do earthquakes in the Basin and Range create fault scarps?
• How does a fault scarp form?
• How many earthquakes have occurred in the Basin and Range Province since 1872?
• Where is most of the stretching, or strain, happening in the western US?
• Do you see a pattern in the way the Basin and Range Province scientific GPS stations are moving? How would you describe it?

Cascadia

• What caused the Coast Range mountains?
• What caused the Cascade Range volcanoes?
• What caused the huge valley between the Cascade Range and the Coast Range?
• Why are there no volcanoes along the coast where the two colliding plates meet?
• What geologic features are directly caused by the subducting Juan de Fuca plate?
• Why are the volcanoes in the Pacific Northwest not located along the coast where the oceanic plate first goes under the continental plate?
• Why are the volcanoes of the Pacific Northwest in a line, rather than spread all over the place?
• What was the location of the largest known earthquake in the lower 48 states?
• Where does episodic tremor and slip occur?
• What causes episodic tremor and slip in subduction zones?
• Why is episodic tremor and slip so interesting?

Seismology and Earthquakes

• What is a plate boundary?
• Why do tectonic plates move?
• Are any of the states in the US free of earthquake hazard?
• How can earthquakes occur in the middle of a tectonic plate?
• What is seismic intensity?
• How do we estimate earthquake magnitude from intensity measurements for older earthquakes that were not recorded with seismic instruments?
• What is a seismic hazards map?
• How does the local geology affect seismic hazard maps?
• What do earthquakes have in common with x-rays?
• Why don’t scientists use X-rays to look inside of the earth?
• How do seismic waves make an image of the interior of the Earth?
• How does a dense array of seismometers improve scientific results?
• What is seismic tomography?
• In the seismic tomography images why are there red colors under the Southwestern US and blue colors under the eastern US?
• What should I do during an earthquake?
• Can a seismometer record you walking near a seismic station?
• Can explosions be recorded on seismometers?
• What is paleoseismology?
• What is a lahar?
• What is radiocarbon dating?
• What is liquefaction?
• What factors are necessary for liquefaction to occur?
• What cities are at risk for liquefaction damage?
• What is seismic retrofitting?
• What is a hot spot?
• What is the difference between a strike-slip fault and a reverse fault?

Tsunamis

• What does the word tsunami mean?
• What source causes the most widespread tsunamis?
• Why are there so many tsunamis in countries around the Pacific Ocean?
• When will the next tsunami from an earthquake in the Juan de Fuca subduction zone occur?
• Will people get warning before a tsunami?