7.7 Earthquake Northern Sumatra Indonesia Tsunami Warning

Northern Sumatra, Indonesia (Hollywood Backstage) - On Tuesday, April 6, 2010 22:15:02 UTC a huge 7.7 magnitude earthquake hit Northern Sumatra, Indonesia. The epicenter is located eight miles north of Pulau Udjung Batu Island. The earthquake was 31 km (19.3 miles) deep. TSUNAMI WARNING

... THE TSUNAMI WATCH IS CANCELLED ...   
THIS BULLETIN IS ISSUED AS ADVICE TO GOVERNMENT AGENCIES. 
ONLY  NATIONAL AND LOCAL GOVERNMENT AGENCIES HAVE THE AUTHORITY
TO MAKE  DECISIONS REGARDING THE OFFICIAL STATE OF ALERT IN THEIR
AREA AND  ANY ACTIONS TO BE TAKEN IN RESPONSE.

 

TSUNAMI BULLETIN

ISSUED AT 2322Z 06 APR 2010

THIS BULLETIN IS FOR ALL AREAS OF THE INDIAN OCEAN. ...

A LOCAL TSUNAMI WATCH IS IN EFFECT ...

A TSUNAMI WATCH IS IN EFFECT FOR INDONESIA FOR OTHER AREAS OF THE INDIAN OCEAN REGION...

THIS MESSAGE IS FOR INFORMATION ONLY AT THIS TIME.

THIS BULLETIN IS ISSUED AS ADVICE TO GOVERNMENT AGENCIES.

ONLY NATIONAL AND LOCAL GOVERNMENT AGENCIES HAVE THE AUTHORITY TO MAKE DECISIONS REGARDING THE OFFICIAL STATE OF ALERT IN THEIR AREA AND ANY ACTIONS TO BE TAKEN IN RESPONSE.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS ORIGIN TIME - 2215Z 06 APR 2010 COORDINATES - 2.4 NORTH 97.2 EAST LOCATION - NORTHERN SUMATRA INDONESIA MAGNITUDE - 7.5 MEASUREMENTS OR REPORTS OF TSUNAMI WAVE ACTIVITY

GAUGE LOCATION LAT LON TIME AMPL PER

------------------- ----- ------ ----- --------------- -----

TELUKDALAM ID 0.6N 97.8E 2301Z 0.14M / 0.5FT 16MIN

LAT - LATITUDE (N-NORTH, S-SOUTH) LON - LONGITUDE (E-EAST, W-WEST) TIME - TIME OF THE MEASUREMENT (Z IS UTC IS GREENWICH TIME) AMPL - TSUNAMI

AMPLITUDE MEASURED RELATIVE TO NORMAL SEA LEVEL. IT IS ...NOT... CREST-TO-TROUGH WAVE HEIGHT.

VALUES ARE GIVEN IN BOTH METERS(M) AND FEET(FT). PER - PERIOD OF TIME IN MINUTES(MIN) FROM ONE WAVE TO THE NEXT.

EVALUATION SEA LEVEL READINGS INDICATE A TSUNAMI WAS GENERATED. IT MAY HAVE BEEN DESTRUCTIVE ALONG COASTS NEAR THE EARTHQUAKE EPICENTER.

FOR THOSE AREAS - WHEN DAMAGING WAVES HAVE NOT OCCURRED FOR AT LEAST TWO HOURS THEN LOCAL AUTHORITIES CAN ASSUME THE THREAT IS PASSED. DANGER TO BOATS AND COASTAL STRUCTURES CAN CONTINUE FOR SEVERAL HOURS DUE TO RAPID CURRENTS.

AS LOCAL CONDITIONS CAN CAUSE A WIDE VARIATION IN TSUNAMI WAVE ACTION THE ALL CLEAR DETERMINATION MUST BE MADE BY LOCAL AUTHORITIES. NO TSUNAMI THREAT EXISTS FOR OTHER COASTAL AREAS IN THE INDIAN OCEAN ALTHOUGH SOME OTHER AREAS MAY EXPERIENCE SMALL SEA LEVEL CHANGES AND STRONG OR UNUSUAL COASTAL CURRENTS. ESTIMATED INITIAL TSUNAMI WAVE ARRIVAL TIMES AT FORECAST POINTS WITHIN THE WARNING AND WATCH AREAS ARE GIVEN BELOW. ACTUAL ARRIVAL TIMES MAY DIFFER AND THE INITIAL WAVE MAY NOT BE THE LARGEST. A TSUNAMI IS A SERIES OF WAVES AND THE TIME BETWEEN SUCCESSIVE WAVES CAN BE FIVE MINUTES TO ONE HOUR.

LOCATION FORECAST POINT COORDINATES ARRIVAL TIME -------------------------------- ------------ ------------ INDONESIA SIMEULUE 2.5N 96.0E 2246Z 06 APR BELAWAN 3.8N 98.8E 0233Z 07 APR ADDITIONAL BULLETINS WILL BE ISSUED BY THE PACIFIC TSUNAMI WARNING CENTER FOR THIS EVENT AS MORE INFORMATION BECOMES AVAILABLE. THE JAPAN METEOROLOGICAL AGENCY MAY ISSUE ADDITIONAL INFORMATION FOR THIS EVENT. IN THE CASE OF CONFLICTING INFORMATION...THE MORE CONSERVATIVE INFORMATION SHOULD BE USED FOR SAFETY.

Tectonic Summary

The Banyak Islands, Sumatra earthquake of April 6, 2010 occurred as a result of thrust faulting on or near the subduction interface plate boundary between the Australia-India and Sunda plates. At the location of this earthquake, the Australia and India Plates move north-northeast with respect to the Sunda plate at a velocity of approximately 60-65 mm/yr. On the basis of the currently available fault mechanism information and earthquake depth, it is likely that this earthquake occurred along the plate interface.

The subduction zone surrounding the immediate region of this event last slipped during the Mw 8.6 earthquake of March 2005, and today's event appears to have occurred within the rupture zone of that earthquake. Today's earthquake is the latest in a sequence of large ruptures along the Sunda megathrust, including two M 7.3 earthquakes beneath Simeulue 125 km to the north in 2002 and 2008; a M 9.1 earthquake that ruptured to within 125 km north of this earthquake in 2004; a M 7.9 250 km to the south in 2007; a M 8.4 375 km to the south in 2007; and a M 7.5 260 km to the south near Padang in 2009.