Green+Group

=Click on our names to see what we've been doing in the lab!= =Chris D.= =Devin= =Dylan= =Chris B.= =Shaun= =Houston=

=What is an earthquake?= Click [|here] to see a earthquake. Scroll down to the bottom to see the video. A earthquake is a sudden shaking in the ground. They generate seismic waves. Most Earthquakes are caused by dislocation in the crust. The crust might bend and when the stress exceeds the rocks strength the break and snap into a new position. In the process of breaking seismic waves are made. Some of the vibrations are high enough frequency to be audible while others are very low. These vibrations cause the whole planet to shake. Geologists have found that earthquakes reoccur along faults. The focal depth of a earthquake is the depth from the earths surface to the region where a earthquake energy originates. The focuses of most earthquakes are found in the crust and upper mantle. The energy from the focus speeds out in all directions. Aftershocks can follow a earthquake for several days or weeks. Four out of five earthquakes take place along the pacific rim. Only the lithosphere has enough strength and brittle behavior to fracture a earthquake. Most earthquakes happen along the boundaries of tectonic plates. =How do scientists measure earthquakes?=

=What are seismic waves?= A seismic wave is a wave transferring energy from one spot to another throughout the whole entire world. A seismograph is used to measure seismic waves. Seismic waves are one of the only types of waves. There are many types of waves such as s- waves p- waves which stands for primary waves and secondary waves. P-waves are the fastest body waves. During an earthquake we feel p- waves before any waves. If you felt a s- wave it might eel like a strong jolt. And those are the different waves and facts about them. The stages of an earthquake are 1. surface waves make the ground appear to ripple like the water in the ocean. 2. houses start to be tore down and ripped apart. 3. and finally the earthquake is gone but it will be back someday. Seismic waves are waves that take energy from one place to another inside the earth. There are three different waves; they are primary waves, secondary waves and surface waves. Primary waves are the fastest, they can travel speeds up to 6 and 13 km/sec. Seismic waves are things that move underground and shake the earth. =Where are many of the Earth’s earthquakes happening?= In 1906 an earthquake killed 700 people in San Francisco. ** **Earthquakes occur when two tectonic plates are sliding past each other and get hooked. Then over millions of years they break loose and then earthquakes occur.**
 * Earthquakes are happening in California right now this minute. A major earthquake occurred in Santa Cruz.

=What are scientists doing to try to predict earthquakes?= 