Monday, April 22, 2013

The Iran and China earthquakes as captured by the UNH seismometer

This past week has been has been a tense one for sure. Not only was there the Boston Marathon bombings and the fertilizer plant explosion in Texas, but there were also major earthquakes in both Iran and China.

The 7.8 magnitude event in Iran occurred on April 16th, near the Iran/Pakistan border. Pakistan bore the brunt of the quake, with at least 35 dead and an entire town essentially destroyed. You can view all the scientific/technical details of the event on its USGS page. We can see the earthquake quite clearly on the UNH seismometer. The event hits our station at 10:56 UTC (06:56 am EST). The shaking intensity when the surface wave hits is strong enough that the seismic wave looks clipped in the display (in green).

The magnitude 6.6 earthquake in China struck on April 20th. Although smaller than the Iran earthquake, this earthquake was very shallow and hit a more densely populated area. The latest estimates put the death toll at 188, with over 11,000 people injured and many are still missing. The USGS page for the event can be seen here.

It takes about 13 minutes for the initial P-wave from the earthquake to reach our station, and you can see when it hits if you look at the top black line. Just after the 30-minute mark on the same line, you can see the S-wave hit. The much larger amplitude surface waves can be seen in red, starting about 21:03 EST.

These earthquakes have devastated the villages they have hit, particularly the one in China. Construction in these small towns is often very old and not up to code. Landslides bury entire structures and block roadways, making it hard for aid to get to those who need it the most. 

My thoughts go out to everyone affected by this past's weeks events, both here in the US and abroad.

The UNH seismometer is part of the larger New England Seismic Network. You can visit their page here.

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