Geology And Geophysics

How Scientists Study Earthquakes



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Scientists who study earthquakes are called seismologists. By analyzing a seismograph, seismologists can tell the strength and distance of the earthquake; however, to find the epicenter, at least two other seismograph readings for the same earthquake are necessary. A seismograph is an instrument that registers the movement of the Earth's tectonic plates caused by seismic waves. Geologists study earthquakes using Global Positioning system (GPS) receivers placed along fault lines. GPS measures movements of the Earth's crust with a precision of one millimeter per year. Scientists make use of diverse technologies for studying earthquakes.

A seismologist is a person that specializes in geophysics, and who studies earthquakes and the mechanical characteristics of the Earth. In addition, seismologists interpret the geological composition and structure of the Earth. Most seismologists are employed in the petroleum industry, where seismic waves come from the explosions generated by underground exploration. Other seismologists study seismic waves generated by natural forces, such as earthquakes. The main function of a seismologist is to detect the source, nature, and the magnitude of a seismic event.

A seismograph is an instrument that registers information of a seismic disturbance, including intensity, duration and direction. Moreover, a seismograph can record the ocean's tidal waves, large explosions, and other events known to cause the shaking of the Earth's surface. A classical seismograph records seismic waves by utilizing a weighed pendulum that vibrates during an earthquake, generating zigzagging lines on a piece of paper. Modern seismographs can operate remotely, sending seismic information back and forth to a recording station. By studying earthquakes, seismologists have mapped the mantle of the Earth.

Global Positioning Satellite Systems (GPS) has become the geodetic method for studying the deformation of the Earth's crust associated with earthquakes. The system detected small movements of the Earth's crust during the June 1992 and January 1994 earthquakes in Southern California. NASA and a group of universities known as (READI) are testing the system along the Northwest Geodetic Array. The system consists of hundreds of GPS receivers scattered along the U.S. Pacific coast. When seismic waves hit the sensors, a warning signal is issued which helps officials detect the epicenter of the earthquake.

A theodolite is a precision instrument used to measure angles. A theodolite is principally utilized for surveying applications; however, the Department of Geosciences of the San Francisco State University uses theodolites to measure the angle formed by three fixed points.  The amount of slide is calculated trigonometrically. The precision of the measurement allows geologists to detect any movement of the Earth's crust. Any movement in the range of 1-2 mm between successive measurements can be detected.

Variations observed in samples of rock and sediment from the depths of the Pacific Ocean could help scientists understand the cause of large damaging earthquakes. The samples were collected from the ocean floor near the coast of Costa Rica. Scientists intend to utilize the samples to gain a better understanding of processes that originate large earthquakes at subduction zones. Some factors that contribute to seismic activity include type of rock and composition, temperature differences, and the way in which water moves within the Earth's crust.

The Quake Catcher Network (QCN) is a research project which makes use of internet-connected computers to study earthquakes. People from around the world can participate by installing a program on their computer. QCN intends to detect earthquakes more efficiently than the traditional seismic networks. QCN intends to gain a better understanding of the processes involved in earthquakes, as well as designing new ways to detect and differentiate earthquakes in real time. QCN forms part of the Stanford University Scholl of Earth Sciences.

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ARTICLE SOURCES AND CITATIONS
  • InfoBoxCallToAction ActionArrowhttp://www.earthquakescanada.nrcan.gc.ca/info-gen/seismolog-eng.php
  • InfoBoxCallToAction ActionArrowhttp://pangea.stanford.edu/research/CDFM/pdfs2/segall1997.pdf
  • InfoBoxCallToAction ActionArrowhttp://earthquake.usgs.gov/research/external/reports/03HQGR0080.pdf
  • InfoBoxCallToAction ActionArrowhttp://www.sciencedaily.com/releases/2011/06/110630112632.htm
  • InfoBoxCallToAction ActionArrowhttp://qcn.stanford.edu/sensor/