Earthquake on 28 March 2005

An earth-quake that measured 8.5 on the Richter Scale of the West Coast on Northern Sumatra. 

The seismographs at Lamont Doherty Earth Observatory at Columbia University in New York, USA shows that after 1600 GMT on March 28th, oscillations start appearing. The seismograph for the previous day too is shown showing regular activity. (Please click on the images to view a larger image). 

Seismographs at Lamont Doherty Earth Observatory

The Pacific Tsunami Warning Center Detected the Earthquake and after 15 minutes issued a communique to Pacific Islands saying that there shall be no threats to them and also advises that there is a Tsunami watch going on but not an alert. 65 minutes later a second communique repeats the same information and says that there may a possibility of a Tsunami at the epicenter.

TSUNAMI BULLETIN NUMBER 003
PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS
ISSUED AT 2226Z 28 MAR 2005

THIS BULLETIN IS FOR ALL AREAS OF THE PACIFIC BASIN EXCEPT
ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA.

... TSUNAMI INFORMATION BULLETIN ...
NOTE CORRECTED EARTHQUAKE PARAMETERS.

THIS MESSAGE IS FOR INFORMATION ONLY. THERE IS NO TSUNAMI WARNING
OR WATCH IN EFFECT.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

 ORIGIN TIME -  1610Z 28 MAR 2005
 COORDINATES -   2.3 NORTH   97.1 EAST 
 LOCATION    -  NORTHERN SUMATERA  INDONESIA
 MAGNITUDE   -  8.5

MEASUREMENTS OR REPORTS OF TSUNAMI WAVE ACTIVITY

 GAUGE LOCATION        LAT   LON    TIME    AMPL    PER
 -------------------  ----- ------  -----  ------  -----
 GAN                   0.7N  73.2E  2023Z   0.05M  34MIN
 MALE                  4.2N  73.5E  2026Z   0.09M  46MIN
 HANIMAADHOO           6.8N  73.2E  2043Z   0.20M  36MIN
 
 TIME - TIME OF THE MEASUREMENT
 AMPL - AMPLITUDE IN METERS FROM MIDDLE TO CREST OR MIDDLE
        TO TROUGH OR HALF OF THE CREST TO TROUGH
 PER  - PERIOD OF TIME FROM ONE WAVE CREST 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 NO MAJOR WAVES ARE OBSERVED FOR TWO HOURS        
 AFTER THE ESTIMATED TIME OF ARRIVAL OR 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.          
                                                                     
 COUNTRIES IN THE BAY OF BENGAL AND ANDAMAN SEA REGIONS SHOULD 
 EXPECT DECREASING WAVE HEIGHTS WHERE OBSERVED. 
 
 IT IS UNKNOWN IF A DESTRUCTIVE TSUNAMI THREAT EXIST FOR OTHER
 REGIONS OF THE INDIAN OCEAN.

THIS WILL BE THE FINAL BULLETIN ISSUED FOR THIS EVENT UNLESS
ADDITIONAL INFORMATION BECOMES AVAILABLE.

THE WEST COAST/ALASKA TSUNAMI WARNING CENTER WILL ISSUE BULLETINS
FOR ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA.

TSUNAMI BULLETIN NUMBER 002
PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS
ISSUED AT 1841Z 28 MAR 2005

THIS BULLETIN IS FOR ALL AREAS OF THE PACIFIC BASIN EXCEPT
ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA.

... TSUNAMI INFORMATION BULLETIN ...

THIS MESSAGE IS FOR INFORMATION ONLY. THERE IS NO TSUNAMI WARNING
OR WATCH IN EFFECT.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

 ORIGIN TIME -  1610Z 28 MAR 2005
 COORDINATES -   2.3 NORTH   97.1 EAST 
 LOCATION    -  NORTHERN SUMATERA  INDONESIA
 MAGNITUDE   -  8.5

EVALUATION

 THIS EARTHQUAKE IS LOCATED OUTSIDE THE PACIFIC. NO TSUNAMI THREAT   
 EXISTS TO COASTLINES IN THE PACIFIC.                                
   
NOTE:
THERE HAS BEEN NO MAJOR TSUNAMI OBSERVED NEAR THE EPICENTER. 

THERE WAS HOWEVER A SMALL TSUNAMI OBSERVED ON THE COCOS TIDE GAGE. 
 WARNING... THIS EARTHQUAKE HAS THE POTENTIAL TO GENERATE A WIDELY   
 DESTRUCTIVE TSUNAMI IN THE OCEAN OR SEAS NEAR THE EARTHQUAKE.       
 AUTHORITIES IN THOSE REGIONS SHOULD BE AWARE OF THIS POSSIBILITY    
 AND TAKE IMMEDIATE ACTION.  THIS ACTION SHOULD INCLUDE EVACUATION   
 OF COASTS WITHIN A THOUSAND KILOMETERS OF THE EPICENTER AND CLOSE   
 MONITORING TO DETERMINE THE NEED FOR EVACUATION FURTHER AWAY.       
                                                                     
 THIS CENTER DOES NOT HAVE SEA LEVEL GAUGES OUTSIDE THE PACIFIC      
 SO WILL NOT BE ABLE TO DETECT OR MEASURE A TSUNAMI IF ONE WAS       
 GENERATED. AUTHORITIES CAN ASSUME THE DANGER HAS PASSED IF NO       
 TSUNAMI WAVES ARE OBSERVED IN THE REGION NEAR THE EPICENTER         
 WITHIN THREE HOURS OF THE EARTHQUAKE.                               

THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT UNLESS
ADDITIONAL INFORMATION BECOMES AVAILABLE.

THE WEST COAST/ALASKA TSUNAMI WARNING CENTER WILL ISSUE BULLETINS
FOR ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA.

Tsunami Bulletins by Pacific Tsunami Warning Center

Magnitude 8.7

Date-Time Monday, March 28, 2005 at 16:09:36 (UTC) = Coordinated Universal Time
Monday, March 28, 2005 at 11:09:36 PM = local time at epicenter

Location 2.076°N, 97.013°E

Depth 30 km (18.6 miles) set by location program

Region NORTHERN SUMATRA, INDONESIA

Distances 
205 km (125 miles) WNW of Sibolga, Sumatra, Indonesia
245 km (155 miles) SW of Medan, Sumatra, Indonesia
535 km (330 miles) WSW of KUALA LUMPUR, Malaysia
1410 km (880 miles) NW of JAKARTA, Java, Indonesia

Location Uncertainty horizontal +/- 4.8 km (3.0 miles); depth fixed by location program

Parameters Nst=289, Nph=289, Dmin=537 km, Rmss=0.76 sec, Gp= 25°,
M-type=teleseismic moment magnitude (Mw), Version=R

Source USGS NEIC (WDCS-D)

Event ID usweax

 
Felt Reports At least 1000 people killed, 300 injured and 300 buildings destroyed on Nias; 100 people killed, many injured and several buildings damaged on Simeulue; 200 people killed in Kepulauan Banyak; 3 people killed, 40 injured and some damage in the Meulaboh area, Sumatra. A 3-meter tsunami damaged the port and airport on Simeulue. Tsunami runup heights as high as 2 meters were observed on the west coast of Nias and 1 meter at Singkil and Meulaboh, Sumatra. Felt (VI) at Banda Aceh and (V) at Medan. At least 10 people were killed during evacuation of the coast of Sri Lanka. Felt (IV) along the west coast of Malaysia; (IV) at Bangkok and (III) at Phuket, Thailand; (III) at Singapore; (III) at Male, Maldives. The quake was also felt in the Andaman and Nicobar Islands, India and in Sri Lanka. Tsunami wave heights (peak to trough) recorded from selected tide stations: about 40 cm on Panjang, Indonesia; about 25 cm at Colombo, Sri Lanka; 40 cm on Hanimadu, 18 cm at Male and 10 cm at Gan, Maldives. Initial observations indicate about 1 meter of subsidence on the coast of Kepulauan Banyak as well as 1 meter of uplift on the coast of Simeulue. Seiches were observed on ponds in West Bengal, India.

Information on the earthquake at USGS

Simulation Results of PMEL Tsunami Research Program of U.S. National Oceanic and Atmospheric Administration (NOAA)

Model Simulation Results - Information on MOST model

Preliminary model result for the maximum height of the tsunami wave at each grid point. The source model is very simple -- a rectangular fault plane encompassing the epicenter, with orientation appropriate to the local tectonics and slip value that results in a magnitude 8.5 earthquake. These results are qualitative at this point. An amplitude scale will be added after comparison with field observations.

Information on the earthquake at Tsunami Research Program