Showing posts with label Jan Mayen Island. Show all posts
Showing posts with label Jan Mayen Island. Show all posts

Friday, August 31, 2012

Two earthquakes off the coast of Jan Mayen Island

Two earthquakes struck the waters off the coast of Jan Mayen Island on August 30, 2012. One had  a magnitude of 6.8 on the Richter Scale and occurred at 13:43 pm (UTC), and was followed eight minutes later by a second one with a magnitude of 5.2 on the Richter Scale that took place on 13:51 pm (UTC).

The location of the earthquakes is indicated by the blue square on the top left of the USGS map below.

The Google map below shows that the location is on fault line extending north into the Arctic Ocean.

The map below shows the two earthquakes at the top in orange. The map shows all earthquakes with a magnitude 5.0 or higher that happened worldwide from August 1 to 30, 2012.

The largest earthquake in August 2012 was a magnitude 7.7 quake on August 14 in the Sea of Okhotsk, close to Sakhalin, Russia's largest island.  With a depth of 626 km (389 miles), it was a "deep-focus" earthquake. Such quakes can be felt at great distance from their epicenters.

As the above map shows, this 7.7 M earthquake and the two recent ones off the coast of Jan Mayen Island occurred on the same fault line that goes over the Arctic. The danger is that further earthquakes on this fault line could destabilize methane hydrates in the Arctic, triggering release of huge amounts of methane.

The map below, from this page, shows fault lines and elevation in meters.

In 2011, a number of posts were added on this topic at knol, which has meanwhile discontinued. These posts have been preserved at the following pages:
Methane linked to Seismic Activity in the Arctic
Runaway warming
Thermal expansion of the Earth's crust necessitates geoengineering