On Sunday morning local time a magnitude 6.5 earthquake rocked the remote Antarctic island of Elephant Island. At the top of the South Shetland Island group, Elephant Island is best known as the place where the shipwrecked mariners of Sir Ernest Shackleton’s 1914 Endurance expedition took shelter and waited for rescue under the leadership of Frank Wild.
Elephant Island is visited by many vessels sailing down to the Antarctic Peninsula from South Georgia Island although terrible weather conditions and the large ocean swells that are common normally restrict visitors to the ship. Landings are very rare. There are no nearby human populations.
One cruise ship has already altered its itinerary to avoid the area.
Here’s an original report, with updates.
Most important Earthquake Data:
Magnitude : 6.6
UTC Time : Sunday, January 15, 2012 at 13:40:18 UTC
Local time at epicenter : Sunday, January 15, 2012 at 09:40:18 AM at epicenter
Depth (Hypocenter) : 10 km
Approx. 100 km from Elephant island, South Shetland Islands
539 km (334 miles) W of Coronation Island, South Orkney Islands
625 km (388 miles) NE of Palmer Station, Antarctica
Very strong earthquake approx. 100 km out of the coast of Elephant Island, an island which is often visited byAntarctica cruiseliners. The island is covered with glaciers. Elephant Island and the smaller islands around are all crowded with antarctic birds and animals. Various penguin colonies like gentoo and chinstrap, seals, etc are common on these islands.
If people were visiting Elephant Island (09:40 is about the time to have shore zodiac excursions), they will have experienced a strong MMI VI shaking.The Antarctic peninsula, with a number of Antarctic stations will have experienced a light shaking.
Update : The earthquake occurred in a very complex tectonic area were 3 different plates are interacting. Todays both earthquakes where more in the direct vicinity of a transform faulting zone. Since 1900, 3 massive 7+ earthquakes occurred in the greater area, 1 along the spreading ridge zone and 2 close to the transform faults. The scars in the seabed reveal the stress along the transform fault zone.
Update : Very strong aftershock of M 6.2. We expect many more aftershocks to happen the following hours and days.
Update : As it is Antarctica summer and thus Tourist season, at least a couple of thousand people may have been walking on one of the many penguin islands of the Antarctic peninsula and may have felt the earthquake. An M 6.6 earthquake will be probably felt within a radius of several hundred km.
Update : The magnitude has been lowered by USGS to 6.5, a lot less energy than the initial 6.7. The earthquakes can be compared with the many earthquakes who are occurring at the South Sandwich Islands, islands with similar animals.
The South Shetland Islands are a group of Antarctic islands, lying about 120 kilometres (75 mi) north of the Antarctic Peninsula, with a total area of 3,687 square kilometres (1,424 sq mi). By the Antarctic Treaty of 1959, the Islands’ sovereignty is neither recognized nor disputed by the signatories and they are free for use by any signatory for non-military purposes.
NO tsunami risk exist for populated islands (there are no people living within a radius of several hundred km). Additionally a M 6.7 earthquake is seldom generating a tsunami. See Below for an extract.
TSUNAMI STATEMENT NUMBER 1
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
1350 UTC SUN JAN 15 2012
AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS
ORIGIN TIME – 1340Z 15 JAN 2012
COORDINATES – 60.7 SOUTH 56.7 WEST
LOCATION – SOUTH SHETLAND ISLANDS
MAGNITUDE – 6.7
A DESTRUCTIVE WIDESPREAD TSUNAMI THREAT DOES NOT EXIST BASED ON
HISTORICAL EARTHQUAKE AND TSUNAMI DATA.
HOWEVER – THERE IS THE SMALL POSSIBILITY OF A LOCAL OR REGIONAL
TSUNAMI THAT COULD AFFECT COASTS LOCATED USUALLY NO MORE THAN A
FEW HUNDRED KILOMETERS FROM THE EARTHQUAKE EPICENTER. AUTHORITIES
IN THE REGION NEAR THE EPICENTER SHOULD BE MADE AWARE OF THIS
THIS WILL BE THE ONLY PRODUCT ISSUED BY THE PACIFIC TSUNAMI
WARNING CENTER FOR THIS EVENT UNLESS ADDITIONAL INFORMATION