Compute the magnitude of an earthquake using what geologists see from ground
ruptures.
The seismic moment and moment magnitude measures the size of an earthquake
based on its physical dimensions rather than on the amplitude of the seismic
waves it emitts. The seismic moment can also be estimated from the low
frequency amplitudes of seismograms.
After an earthquake, you can enter the earthquake parameters until the
magnitude matches the given Richter
magnitude from the news. This will give you an ideal of the physical
size of the earthquake. The fault width is usually no larger than 20 km
because thats the width of the crust
unless its a subduction
zone type earthquake. |
Values averaged over many earthquakes
| Mw |
Length (km) |
Height (km) |
Slip (m) |
Duration(sec) |
| 4 |
1 |
1 |
0.05 |
< 0.3 |
| 5 |
3 |
3 |
0.15 |
0.5-1.0 |
| 6 |
10 |
10 |
0.5 |
1.7-3.3 |
| 7 |
30 |
30 |
1.5 |
5-10 |
| 7 |
50 |
20 |
1.5 |
8-17 |
| 8 |
200 |
50 |
5.0 |
33-67 |
| 8 |
400 |
20 |
6.5 |
> 60 |
|
|
University Nevada Reno
Seismological Laboratory