EarthQuakes & Volcanoes (e.g. Shake and Bake). The most visible manifestations of the earth’s internal heat are earthquakes and volcanoes. There is an interesting relationship between the two that led researchers in the 1960’s to overturn our view of the Earth. Igneous Rocks.
Earthquakes/Volcanoes Occur along Linear Belts. The most famous of these regions is called the “Pacific Ring of Fire”
Shield Volcanoes tend to be very large, but not as steep or tall (with respect to the land surface) as Composite volcanoes.
Shield volcanoes tend to be dominated by basaltic volcanism.
Eruption of Kiluaea, Hawaii
Mt. Capulin, New Mexico
Difference in P-S gives an estimate of distance, but not direction. In essence, we end up with a ‘circle of possible locations’ for each station.
Epicenter: Point on the earth’s
Surface directly above the focus
Sample Formula would look like:
Mag= log (A/T) + log D + 3.2
Where A=amplitude (mm)
T= period (seconds)
And the last number is a station correction.
Hanging Wall: Miners hang their lamps on it. Foot wall is the side of the fault that miners could walk on.
Left-lateral motion: Observers standing on opposite sides of the fault would see each other moving to their left.
Right-lateral motion: Observers standing on opposite sides of the fault would see each other moving to their right.
Strike-Slip Fault Plane Solution---In this case a right lateral fault.
Reverse Fault Focal Mechanism
Case 2: Layer 2 is ‘slower’ than Layer 1
Case 1: Layer 2 is ‘faster’ than Layer 1
Earthquake damage depends on many variables. For example:
How Deep was the quake? The deeper the quake, the less likely to see damage at the surface.
How Big was the quake? Larger magnitudes cause more damage.
What time did the earthquake occur? Crowded buildings, streets etc may result in more death.
What are building codes? Places such as California and Japan have rigid earthquake building codes so a mag 6 quake is less likely to cause severe damage there than in a highly populated region with poor/no building codes.
Number & Size of aftershocks- Large aftershocks can destroy damaged buildings.
Tsunami is an wave generated most commonly by earthquakes; however,
Tsunami’s can also form when large chunks of ice calve off into the ocean
Or massive landslides fall into the sea. They are most commonly the result
Tsunami’s are sometimes called ‘tidal waves’ or seismic sea waves.