What’s up? The Friday links (43)

Two really strong earthquakes happened yesterday at the Mid-Atlantic Ridge in the Jan Mayen Islands area. The first one had a magnitude of M6.6, the second one, around ten minutes later, had M5.3. Moment tensor solutions show clear strike slip along a transform fault west of the ridge. The seismicity map shows that events like yesterday’s don’t come as a suprise:

Seismicity 1960 - today (Image courtesy of EMSC)
Moment tensor solutions - clear strike-slip (image courtesy of EMSC)

Curiosity’s adventures

Curiosity is doing exciting things on Mars currently – testing its wheels and the robotic arm, sending images that look like taken somewhere in Utah, and killing cats:

Accretionary Wedge #49

Don’t miss Dana Hunter‘s Accretionary Wedge #49: Out of this World. We can expect some nice exogeology post like this one by Jesscia Ball.

Rockfall in Grand Canyon

Small rockfalls do regularily occur in the Grand Canyon, but it’s rather rare to see images from that happening. Wayne Ranney was that happy and his student captured a rockfall happening.

An earthquake swarm in California

Close to Brawley, southern California, residents did not come to sleep since last Saturday. An earthquake swarm with hundreds of events rattled the area close to Salton Sea, with the strongest event reaching M>5. Read some post about this series over at Arizona Geology, Geotripper and Volcano Science and News Blog.

The swarm centre located between Salton Sea and Mexicali (image courtesy of GoogleEarth/USGS)

Magnitude 7.3 EQ off El Salvador

An earthquake with a magnitude of 7.3 happened ~100 km off El Salvador in a depth of 20 km. No damages occurred and no one was harmed, but a small tsunami was observed (tsunami early warning system did work well, warnings had been cancelled soon). The Pacific Tsunami Warning system published the following measurements:

Gauge location        LAT   LON      TIME        AMPL         PER
———————————————————————————–
LA UNION SV          13.3N  87.8W  0627Z   0.02M /  0.1FT  08MIN
DART 43413           10.8N 100.1W  0619Z   0.01M /  0.0FT  10MIN
ACAJUTLA SV          13.6N  89.8W  0540Z   0.10M /  0.3FT  08MIN

Historic moment tensor solutions (Image courtesy of USGS)

Sand as seismic source

New Zealand’s GNS has conducted a nice experiment to investigate an active volcano: Sand as seismic source. You might ask yourself “How can sand act as seismic source?” Well, just take several hundreds of kilos and drop them from 300 m!

Have a nice weekend!

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