<p>The energy of an earthquake can be calculated from the <a href="http://en.wikipedia.org/wiki/Moment_magnitude_scale" rel="nofollow">moment magnitude scale</a> value alone. Two earthquakes of different duration, but the same moment magnitude, have the same energy.</p>

<p>The destructive effect of an earthquake is described by the intensity, and a scale such as the <a href="http://en.wikipedia.org/wiki/Mercalli_intensity_scale" rel="nofollow">Mercalli Intensity scale</a>. </p>

<p>I believe there were reports that the ground motion during the Nepal earthquake (Susan Hough of USGS on BBC) had a longer period and shorter duration than initially estimated. This would mean a lower ground acceleration and duration of shaking for the magnitude.  Greater destruction might have resulted if the earthquake (with the same magnitude) had had a longer duration or higher ground acceleration.</p>

<p>The local ground motion (period, acceleration and duration) during an earthquake vary with location due to factors such as underlying geology, fault mechanism, and orientation to fault. This is one reason that following an earthquake seismologists construct a map of earthquake intensity. As the USGS scientist said in her interview, working out the details is a research project. </p>

CC BY-SA 3.0
2015-05-21T12:42:46.180Z
What might have caused for slower ground option and low ground acceleration?
Four Seasons
CC BY-SA 3.0
2015-05-21T12:39:39.343Z
2015-05-21T13:33:10.003Z
2015-05-21T13:33:10.003Z
Mark Rovetta
<p>I am asking this question in reference to the recent earthquake that struck Nepal last month. I read that the magnitude 7.8 richter scale earhtquake would have caused more damage had it lasted for longer time. In case of Nepal it lasted for nearly 30 seconds. I also read that that magnitude scale was not able to release all the energy that has been stored in the form of strain in the plate.</p>

<p>So what I wanted to ask is that if that earthquake had lasted for more time, would it have released more energy? Similarly does an earthquake of magnitude, say 6, would release energy just as equal to 7.8 if it lasted for more time?</p>

CC BY-SA 3.0
2015-05-21T04:06:11.953Z
Are you referring to reports that ground shaking during the Nepal earthquake was slower than expected? [The Destructive Power of the Nepalese Earthquake] (http://www.bbc.co.uk/programmes/p02q9qmg)
Mark Rovetta
CC BY-SA 3.0
2015-05-21T04:09:45.670Z
Yes, there were many reports about that.
Four Seasons
<geophysics><earthquakes>
The relation between the magnitude and duration of earthquake
Four Seasons
# The relation between the magnitude and duration of earthquake

(Asked by: username_0 on 2015-05-18)

I am asking this question in reference to the recent earthquake that struck Nepal last month. I read that the magnitude 7.8 richter scale earhtquake would have caused more damage had it lasted for longer time. In case of Nepal it lasted for nearly 30 seconds. I also read that that magnitude scale was not able to release all the energy that has been stored in the form of strain in the plate.

So what I wanted to ask is that if that earthquake had lasted for more time, would it have released more energy? Similarly does an earthquake of magnitude, say 6, would release energy just as equal to 7.8 if it lasted for more time?

**Tags:** geophysics, earthquakes

> **Comments:**
> **username_1**: Are you referring to reports that ground shaking during the Nepal earthquake was slower than expected? [The Destructive Power of the Nepalese Earthquake] (http://www.bbc.co.uk/programmes/p02q9qmg)  
> **username_0**: Yes, there were many reports about that.  

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## 1 answers

### Answer by username_1 on 2015-05-21. Score: 2

The energy of an earthquake can be calculated from the [moment magnitude scale](http://en.wikipedia.org/wiki/Moment_magnitude_scale) value alone. Two earthquakes of different duration, but the same moment magnitude, have the same energy.

The destructive effect of an earthquake is described by the intensity, and a scale such as the [Mercalli Intensity scale](http://en.wikipedia.org/wiki/Mercalli_intensity_scale).

I believe there were reports that the ground motion during the Nepal earthquake (Susan Hough of USGS on BBC) had a longer period and shorter duration than initially estimated. This would mean a lower ground acceleration and duration of shaking for the magnitude. Greater destruction might have resulted if the earthquake (with the same magnitude) had had a longer duration or higher ground acceleration.

The local ground motion (period, acceleration and duration) during an earthquake vary with location due to factors such as underlying geology, fault mechanism, and orientation to fault. This is one reason that following an earthquake seismologists construct a map of earthquake intensity. As the USGS scientist said in her interview, working out the details is a research project.

> **Comments:**
> **username_0**: What might have caused for slower ground option and low ground acceleration?  

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