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:
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
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.
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
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!