Earthquake Magnitude Calculator for the AS-1 Seismograph
Magnitude is an estimate of the energy release or size of an earthquake. The estimates are calculated from the amplitude of wave energy on a seismograph adjusting for the magnification of the seismograph and the distance of the seismograph station from the earthquake. Click here for more details and examples of magnitude calculation using the AS-1 seismograph. A detailed discussion about the different kinds of magnitudes can be found at the USGS site.
earthquake magnitude calculator is designed for the AS-1 Seismograph.
Specifications of the instrument can be found at web.ics.purdue.edu/~braile/edumod/as1mag/as1mag.htm.
The description and examples presented here are for the AS-1 vertical component
seismograph and the AmaSeis Software. The AmaSeis
program connects the AS-1 seismograph to a computer running Windows, provides a
continuous seismic record on the monitor, and includes several display and
analysis tools. The seismograph records shown here were recorded using an AS-1
Things to know before using the Calculator:
The calculator needs three inputs to measure the desired magnitude. The user must supply the Amplitude (in digital units; this amplitude is converted by the calculator to microns of ground displacement using seismometer characteristics determined by calibration of the seismometer), the Period (in seconds) and the Distance (in degrees, geocentric angle). The terms are briefly explained here. For more details, please visit the links shown above.
Epicentral Distance vs. Surface Distance
(D=Distance in degrees)
a folder (~2.4MB) that contains a version of the AS-1 Magnitude Calculator that
can be run locally on your computer. Last modified
ã Copyright 2003. L. Braile. Permission granted for reproduction for non-commercial uses.