Unformatted text preview: Name: SIO 15: Homework 2 (Lectures 6,7,8) - Fall Quarter 2007 - Due October 19th 1) Describe the 3 different types of plate boundaries (sketch if needed). (3pts) Transform boundary- Boundary in which plates slide, or grind past each other along transform faults in strike-slip motion (sinistral/left-lateral or dextral/right-lateral). Lateral stress regime in which only horizontal motion occurs. Divergent boundary- Boundary in which two plate slip (or pull) away from each other forming a spreading center or rifting zone. Extensional stress regime in which normal faulting occurs. Hanging block slides down on lower foot block. Convergent boundary- Boundary in which two plates slide toward each other, eventually colliding causing either a subduction zone or a continental collision. Compressional stress regime in which reverse or thrust faults occur. Hanging block slides over the foot block. 2) Sketch and explain the differences between the following faults: (6pts) Normal Fault: Reverse Fault: Strike-Slip Fault: 3) Explain how one would locate an earthquake (2pts) and define the two types of waves that are measured. (1pts) -Need at least 3 seismograms to find epicenter (4 for hypocenter) -Triangulation is preformed with P-S wave differential times -Draw circle with P-S times around each station -Center of common area is the epicenter/hypocenter P waves- Primary wave; first to arrive at station. Compressional waves that travel straight through the Earth and have particle motion in the direction of wave propagation. Equivalent to sound waves. S waves- Secondary waves; second to arrive at station. Shear waves that travels straight through the Earth and have particle motion perpendicular to the direction of wave propagation. Equivalent to waves on a string or light waves. 4) Define a volcano and describe how a typical eruption occurs. (2pts) List at least 4 possible volcanic hazards. (4pts) Volcano (typical)- A structure at the surface that is formed during volcanism (transforming magma to lava). Typically has a crater, vent, and a magma chamber. Eruption- Rock melts (via decompression or volatiles) and escapes through an opening (crater or crack). The eruption is driven by the process of dissolved gases becoming released as decompression occurs. -Lava flows -Ash/tephra fall -Lahars -Pyroclastic flows -Earthquakes -Tsunamis -Gas exhalations -Climate change -Erosion -Submarine landslides 5) (Earthwatch) How many times in the past 40 years has New Zealand's Mount Ruapehu erupted, and what types of volcanic hazards occurred in its most recent eruption? (2pts) Mount Ruapehu has erupted 5 times in the past 40 years. Some volcanic hazards present were mud and ash flows/falls. ...
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- Fall '08
- Plate Tectonics, stress regime, Mount Ruapehu