# Research Paper Assignment 2:Topic 2

## How an Earthquake epicenter and magnitude is determined:

http://academics.concord.edu/sckuehn/virtualearthquakes.pdf In order to locate the epicenter of an earthquake, you need to estimate the time interval between the arrival of the P and S waves (the S-P interval) on the seismograms from at least three different stations. You have to measure the interval to the closest second and then use a graph to convert the S-P interval to the epicentral distance.

To determine magnitude of an earthquake there are many ways one could evaluate: from the cost of repairs resulting from damage, from the length of rupture of the earthquake fault, from the amount of ground shaking, etc. But determining the strength of an earthquake using these kinds of "estimators" is full of potential problems and subjectivity.

A well-known scale used to compare the strengths of earthquakes involves using the records (the seismograms) of an earthquake's shock waves. The scale, known as the Richter Magnitude Scale created by Dr. C. F. Richter. The Richter magnitude determination is based on measurements made on seisograms. Two measurements are needed: the S-P time interval and the Maximum Amplitude of the Seismic waves.

## Relationship between an earthquake and a tsunami

A tsunami occurs once an earthquake shakes the bottom of the sea and the impact travels to sea-surface.

## Geophysicist

Someone who studies the Earth using gravity, magnetic, electrical, and seismic methods.