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__Chapter 5 Project-Earthquakes__ Essential Questions: How does the theory of Plate Tectonics affect Earth's surface? How can we better prepare for natural disasters?

Content Question: How does stress in the Earth's crust change our plant's surface?

 San Andreas Fault  

. The San Andreas Fault is an example of a strike-strip fault located near the San Francisco Peninsula in California. It lies on a Transform plate boundary between the North American Plate and the Pacific Plate. The plate movement results from the inner core heating the asthenosphere so that it becomes elastic and begins to move. This change in temperature creates convection currents in the mantle, which ultimately moves the lithospheric plates in different directions. This movement creates pressure that builds up over time.Shearing is a type of stress that causes rocks to break and slip apart which created faults and many times earthquakes.

Click on the link below to take you to an interactive map of the San Andreas Fault region.

Interactive map

l Click on the link below to watch a strike-slip fault animation. strike-slip fault animation

Content Question: How do we monitor and record the intensity of earthquakes?

Geologists use several devices to monitor movement on the ground. The USGS (The United States Geological Society) uses creep meters to monitor and record movement of rocks along a strike-sip fault. Creep meters are made of a wire attached to a post on the other side of the fault. The wire is attached to a weight that moves based on how much the fault moves.

Earthquakes vary in intensity. The magnitude is measured on three different scales: The Richter, Mercalli, and Moment Magnitude scales. Seismic waves are the vibrations from earthquakes that travel through the Earth; they are recorded on instruments called seismographs. Earthquakes with magnitude of about 2.0 or less are usually called microearthquakes; they are not commonly felt by people and are generally recorded only on local seismographs. Events with magnitudes of about 4.5 or greater - there are several thousand such shocks annually - are strong enough to be recorded by sensitive seismographs all over the world.



Content Question: What are the effects of Earthquakes?

shaking turns solid that is moist into liquid mud. This results is buildings and structures quickly sinking into the mud and collapsing.
 * **Type of Effect ** || ** Result ** || **Example ** ||
 * Liquefaction || The process by which violent

The picture on the right shows liquefaction of a road after an earthquake. || ||
 * Tsunami || A destructive effect of an earthquake on the ocean floor. Seismic waves create a crack on oceanic crust which lift up a part to form waves on the open ocean. As the wave moves toward the coast, the waves get larger and larger.

The picture on the right shows a tsunami flooding a road in Japan. || ||
 * <span style="font-family: 'Comic Sans MS',cursive; font-size: 130%;">Aftershocks || A shock with a varying magnitude up to M 6 on the Richter Scale. An aftershock can occur hours, days, or even months after a large quake.

The picture on the right shows destruction of a building in China. The aftershock killed 20 people and injured 480. It also destroyed 71,000 homes in minutes. || ||

<span style="color: #0000ff; font-family: 'Arial Black',Gadget,sans-serif; font-size: 130%;">Content Question: How can we prepare ourselves for an earthquake in our area?