|
|
|
The magnitude of most earthquakes is measured on the Richter scale, invented by Charles F. Richter in 1934. The Richter magnitude is calculated from the amplitude of the largest seismic wave recorded for the earthquake, no matter what type of wave was the strongest.
|
www.geo.mtu.edu/UPSeis/intensity.html
|
|
|
|
|
|
What causes Earthquakes? ... The scale is measured in steps from one upward. Each successive unit is ten times more powerful than the one before. Therefore an earthquake that measures 7.0 on the Richter scale is 1000 times more powerful than an earthquake measuring 4.0. Little damage is done by an earthquake below 4.0;
|
library.thinkquest.org/10136/earthquk/earttq.htm
|
|
|
|
|
|
Two numbers are commonly given to describe earthquakes -- intensity and magnitude. Intensity, also referred to as the "Mercalli scale," is a number based on people's observations (or "felt reports"). It is related to the damage caused by local ground shaking and ground failure.
|
www.mrs.umn.edu/earthquakes/measured.html
www.mrs.umn.edu/earthquakes/measured.html
|
|
|
Next section-- Previous section-- Table of Contents-- Pacific Northwest Earthquakes; ... HOW ARE EARTHQUAKES MEASURED?; taken from "Washington State Earthquake Hazards", by Linda Noson, Anthony Q amar, and Gerald Thorsen;
|
www.geophys.washington.edu/SEIS/PNSN/INFO_GENERAL/NQT/h...
www.geophys.washington.edu/SEIS/PNSN/INFO_GENERAL/NQT/how_are.html
|
|
The vibrations produced by earthquakes are detected, recorded, and measured by instruments call seismographs. The zig-zag line made by a seismograph, called a "seismogram," reflects the changing intensity of the vibrations by responding to the motion of the ground surface beneath the instrument.
|
pubs.usgs.gov/gip/earthq1/measure.html
pubs.usgs.gov/gip/earthq1/measure.html
|
|
|
www.geography.learnontheinternet.co.uk/activities/measu...
www.geography.learnontheinternet.co.uk/activities/measuringearthquakes.html
|
|
