Earthquakes and Earth's Interior Quiz Part 1
About this set
Created by:
leslieharris1 on November 15, 2011
Subjects:
earthquakes, geology, seismology
Description:
Chapter 14 Essentials of Geology by Pearson
Log in to favorite or report as inappropriate.
Order by
41 terms
Terms | Definitions |
|---|---|
 Earthquake | The vibration of Earth produced by the rapid release of energy |
| Focus | The source of the energy that radiates in all directions from here in the form of waves |
| Faults | Large fractures in the Earth's crust that are associated with movements that produce earthquakes |
| Plate Tectonics Theory | Most of the motion along faults can be explained by this |
| Seismology | The study of earthquake waves; dates back to the Chinese almost 2000 years ago |
| Seismologists | People who study earthquakes and their characteristics |
| H.F. Reid | First explained mechanism for earthquakes |
| Mechanism for earthquakes | Rocks on either side of fault are deformed by tectonic forces, bend and store elastic energy, frictional force is overcome |
| Elastic rebound | Slippage at the weakest point (the focus) occurs; vibrations occur as the deformed rock "springs back" to its original shape |
| Focus | Point at the depth where the rocks ruptured to produce earthquakes; place where quake waves originate |
| Aftershocks | smaller quakes produced after a major quake caused by rocks shifting to new positions |
| Foreshocks | small earthquakes that come before a major earthquakes |
| San Andreas | Most studied fault system |
| Fault creep | Slow gradual displacement of some portions of fault |
| 50 to 200 years | Great earthquakes should occur about |
| Seismograph | Instruments that record seismic waves |
| Large hollow jar | Chinese used this to measure seismic activity with suspended free motion mass |
| Seismograms | Records obtained from seismographs |
| Types of seismic waves | Surface, Body |
| Surface waves | Travel along the Earth's surface; cause greatest destruction; slow & great |
| Two kinds of body waves | Primary (P) and Secondary (S) |
| Body waves | Travel through Earth's interior; two types |
| Primary (P) waves | travel 1.7 times faster than S waves; travel through whole interior; motion is back & forth |
| Secondary (S) waves | shaking motion at right angles; travels only through solids; slower velocity than P waves; slightly greater amplitude than P waves |
| Waves | Wavelength, crest, trough and amplitude |
| Epicenter | location on the surface directly above the focus; located using the difference in velocities of P & S waves |
| Three | At least this many station recordings needed to locate an epicenter |
| Travel-time graph | used to determine each station's distance to the epicenter |
| Locating the epicenter | a circle with radius equal to distance to epicenter drawn around each station; point where all 3 circles intersect is epicenter |
| 95% | percent of energy released by earthquakes; originates in a few relatively narrow zones that wind around the globe |
| Major earthquake zones | Circum-Pacific belt, Mediterranean Sea region to Himalayan complex & oceanic ridge system (underwater mountains) |
| 5 to almost 700 km | Range of depths of earthquakes |
| Types of earthquakes | Shallow, Intermediate & Deep Focus |
| Shallow | surface to 70 km; occur along oceanic ridge system; nearly all damaging quakes originate at this depth; not much room so more damage |
| Intermediate | between 70to 300 km |
| Deep Focus | over 300 km; almost all occur in circum-pacific belt |
| 90% | Percent of all earthquakes occur at depths of less than 100 km |
| Two measurements of earthquake size | Intensity and Magnitude |
| Intensity | a measure of the degree of quake shaking at a given locale based on amount of damage |
| Magnitude | estimates the amount of energy released at the source of the quake |
| Modified Mercalli Intensity Scale | developed using CA buildings; drawback not true measure of quakes actual severity; Guiseppe Mercalli; 1-12 in Roman numerals; I - least; XII - most; used after quake |
First Time Here?
Welcome to Quizlet, a fun, free place to study. Try these flashcards, find others to study, or make your own.