Samoa Tsunami Update

Samoa Tsunami: Images and Update

The tsunami occurred after a  massive earthquake measuring up to 8.4 Mw struck in the Samoa Islands Region about 185 km (115 miles) east-northeast of Hihifo, Tonga and 195 km (125 miles) south  of APIA, Samoa.

According to various reports

• A series of of three or more tsunamis struck into the Pacific islands of American and Western Samoa destroying villages
• At least 4 villages were wiped off.
• Dozens of people, including many children, were  swept out to sea

• As many as 100 people have been killed, with many hundred more injured

• U.S. President Obama has declared American Samoa a major disaster area
• A 4-meter (13-foot) wave hit the  northern coast of Tonga.
• A Pacific-wide tsunami warning was issued, but later canceled.

• Japan’s Meteorological Agency (JMA) issued a local tsunami warning for its east coast, warning of a possible tsunami waves measuring up to 50cm.
• The Pacific Tsunami Warning Center later reported that small tsunami waves had indeed reached Hawaii, and warned swimmers and boats that the waves could prove dangerous.
• Several  South Pacific island nations reported rising sea levels.

Formerly Leone village, American Samoa. Photograph: Ardie Roque/EPA. Image may be subject to copyright.

Cont…

• The southern section of American Samoa’s main Tutuila island  was “devastated,” its governor said, with at least 24 people  killed and twice as many injured.
• As video images come in,  the extent of the damage becomes more evident with homes destroyed by the waves, large fishing boats hurled ashore, and vehicles piled on top of each other.
• “Some areas have been flattened and the tsunami brought a lot of sand onshore, so there have been reports the sand has covered some of the bodies,” Western Samoa’s disaster management office said.

• “They are still continuing the searches for any missing bodies in the area,” they said, adding that the southern section of their country’s main island of Upolu was the worst hit.

A section of Fagatogo, Tutuila Island, Pago Pago Harbor, American Samoa, is seen inundated after the tsunami struck. Photograph: Fili Sagapolutele/AP.  Image may be subject to copyright.

Related Links:

• Magnitude 8.3 Quake Strikes Samoa Islands Region
• The Largest Earthquake

Magnitude 8.3 Quake Strikes Samoa Islands Region

Up to 3 More Large EQs Could Strike the Pacific Ring of Fire in 2009

The Next Megaquake May Strike New Zealand

Massive Earthquake Measuring up to 8.4 Mw Strikes Samoa Islands Region

The mainshock occurred on Tuesday, September 29, 2009 at 17:48 UTC [Tuesday, September 29, 2009 at 06:48 AM at epicenter,] which struck at striking at a depth of about 10km.  The mainshock has since been  followed by at least two dozen aftershocks both locally and in the neighboring Tonga region, the largest of which measures 6.2 Mw so far.

Tsunami

The large earthquake generated  1.6-meter  waves in American Samoa, Apia and Pago Pago. The Pacific Tsunami Warning Center (NOAA/NWS/PTWC) issued a tsunami warning which has since been canceled.

According to local news, at least 4 villages were wiped off, leaving more than 40 dead and up to a 100 injured. Most of the casualties are believe to be children. More casualties are expected as local reports are received.

How large was this earthquake?

The GFZ Potsdam – Earthquake Bulletin reported the mainshock as M 8.2, while the European-Mediterranean Seismological Center recorded it as 8.1Mw. However, FEWW believes the quake measured up to 8.4Mw.

On June 26, 1917, a magnitude 8.4 earthquake struck the neighboring Tonga region at a depth of about 25km, some 115 km northwest of today’s event.

Tsunami Location Map

Click on image to enlarge. Source NOAA

This advisory is in effect for California, and Oregon

• A tsunami advisory indicates a tsunami which may produce strong currents and is dangerous to those in or very near the water is expected.
• Large inundations are not expected in areas under advisory status.
• Advisories will be cancelled, extended, or upgraded to a warning depending on the event severity.
• Advisories are issued when the expected tsunami amplitude is in the range of 0.3 to 1 meter.

Tsunami Propagation Map

Click on image to enlarge. Source: NOAA/WCATWC

US Tsunami waves initial arrival times

Tsunami waves initial arrival times including wave amplitude above sea level (ASL) at the US coastal areas.

Click  on image to enlarge. Source NOAA

Tsunami Travel Time Map

Tsunami Travel Time Map. Source NOAA/NGDC. Click on image to enlarge.

Map of Tsunami Advisory – Japan

Map of Tsunami Advisory  for  Japan. Yellow highlights indicate tsunami heights of about 0.5m (50cm). Original Map: Japan Meteorological Agency (JMA). Image may be subject to copyright. Click on image to enlarge.

Earthquake Details

GFZ Potsdam – Earthquake Bulletin
Region: Samoa Islands Region
Time: 2009-09-29 17:48:10.3 UTC
Magnitude: 8.2
Epicenter: 172.04°W 15.49°S
Depth: 10 km
Status: manually revised

© Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum – GFZ

USGS downgraded the mainshock to 8.0Mw.

10-degree Map Centered at 15°S,170°W

Earthquake Location Map. Original Map: USGS. Enhanced by FEWW.

Historic Seismicity (Mag 7 or greater EQs since 1900)

Major Tectonic Boundaries: Subduction Zones -purple, Ridges -red and Transform Faults -green
Original Image: USGS. Enhanced by FEWW.

Related Links:

• The Largest Earthquake
• Earthquakes [Main Index Page]
• Volcanoes
• FEWW Volcano Links
• 1960 Chilean Tsunami
• Indian Ocean Earthquake Triggers Deadly Tsunami and 2004 Indian Ocean earthquake