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A "great" earthquake struck the Banyak, Nias
and Simeulue Islands off the west coast of Sumatra on 28 March
2005 at local time. The earthquake had a magnitude of Mw=8.7 and
caused considerable damage to life & property in the region. A
damaging local tsunami was generated in the vicinity of the
aforementioned islands adding to the damage. This earthquake was
initially believed to have been a large aftershock from the 2004
Sumatra-Andaman earthquake that occurred to the north. It has
since been determined to have been triggered due to changes in the
static stress regime of the region brought about by the 2004 event
and was thus not a large aftershock.
The earthquake
was centred 9
kms W of
Teluk Asin, Pulau Bangkaru (Sumatra), Indonesia,
or 30.7 kms
SW of Alaban, Pulau
Tuangku (Sumatra), Indonesia,
or 67.6 kms ESE of
Pasirtinggi, Simeulue Island (Sumatra),
Indonesia,
or 74.1 kms NW of
Sifahandra, Nias Island (Sumatra), Indonesia,
or
110 kms NW of
Gunungsitoli, Nias Island (Sumatra), Indonesia,
or 250 kms SW of Medan (Sumatra), Indonesia,
or 429 kms SE of Banda Aceh (Sumatra), Indonesia,
or 640 kms SSE of Campbell Bay (Great Nicobar Island), India,
or 780 kms WNW of Changi International Airport, Singapore.
According to a report by the government of Indonesia's
agency for Reconstruction and Rehabilitation,
839 people were killed and 6,279
others were injured in this earthquake.
The island of Nias was hardest hit badly damaging several villages
and the large towns of Gunungsitoli and Telukdalam.
Eyewitness said the shaking was so severe that people could not
stand. Damage also
occurred on the island of Simeulue and in the town of Sinabang in
the southern part of the same island. Parts of the Banyak Islands
sank by as much as 3-feet while parts of Nias such as Lagundri Bay
were uplifted. Damage was also reported at Gunung Meriah, Meulaboh,
Samatiga, Simpang Kiri, Singkil and in the Tapanauli regency on Sumatra.
The earthquake was strongly felt in Banda Aceh, Lhokseumawe, Medan
and in the Bireuen Regency on Sumatra. It was also felt at Bengkulu, Jambi,
Krui, Padang, Pekanbaru and Riau.
At
Banda Aceh, the shock was experienced for nearly 75-seconds.
People had some difficulty standing and eyewitness saw cars and
trucks shaking under the impact of the quake. Panic followed once
the shaking ended and hundreds of people fled to higher ground,
using any means available. Similar scenes of panic were witnessed
at Medan and in other cities in Sumatra.
In
Thailand, the earthquake was felt in many parts of the country. High
rise buildings in the capital, Bangkok and in the city of Hat Yai
were temporarily evacuated. In areas hard hit by the December 2004
tsunami such as Khao Lhak, Krabi, Nakhon si Thammarat, Satun and
Songhkla, people immediately began moving to higher ground once they
felt the earthquake. A few buildings in Hat Yai and Songhkla
suffered minor damage. In Malaysia, the earthquake was felt along
the entire west coast including at Johor, Kedah, Kuala Lumpur,
Langkawi, Muar, Penang, Petaling Jaya, Pontian, Port Klang, Tanjung
Pelepas and Tanjung Piai. Tremors were felt in high-rise buildings
in Alexandra, Bekor, East Coast, Punggol, Rochor, Sengkang, Toa
Payoh, Whampoa, Woodlands in Singapore.
Strong tremors were felt in the Nicobar Islands in India. Farther
north the quake was mildly felt by the occupants in the upper floors
of buildings in Diglipur & Port Blair in the Andaman Islands.
Tremors from this earthquake were not felt on the Indian mainland.
However, seismic seiches were observed in ponds & standing water
bodies at Basanti, Canning, Kolkata and Kulpi in West Bengal. Mild
tremors from the earthquake were felt along the east coast of Sri
Lanka and as far as the Maldives.
A
damaging local tsunami struck Banyak, Nias, Simeulue and the west
coast of Sumatra following the earthquake.
Fearing another tsunami thousands of people fled to higher ground in
Banda Aceh and other parts of coastal Sumatra, Indonesia. A boat off
the Banyak Islands experienced strong swells and unusual currents
for as
long as two hours after the earthquake. A local
tsunami struck Nias Island with wave heights of 4-5 metres
and swept away many people at Sirombu.
A 3-4 metre wave struck the islands of Banyak and Simeulue
and the Sinkil district on Sumatra. At Sinkil, residents reported a
waves of 4-metres, causing flooding upto a metre high in some parts.
A 2-metre wave struck the village of Sirombu on the west coast of
Nias sweeping away a few people. Flooding upto a metre was also
reported from as far north as Meulaboh. The south
coast of the island of Simeulue was struck by a 3-metre tsunami
causing moderate damage to
the port and airport facilities
on Simeulue Island and resulted in at least 100 deaths. On Sumatra, the
tsunami flooded parts of the towns of Meulaboh, Sigli and Singkil.
At Singkil, a tsunami, reported to have been up to 4-metres high
damaged many buildings. At Meulaboh, the sea receeded, drawing out
the water from the river and then returned to flood coast.
The
earthquake did not generate an Indian Oceanwide tsunami although
measurable changes were recorded at many places in the Indian Ocean
basin. Tsunami warnings were issued for many countries in the region
including India and Sri Lanka but were later withdrawn. In Sri
Lanka, the National Aquatic Resource & Development Agency reported
waves with a maximum height of 2.3 metres at Kirinda in southern Sri
Lanka. According to the Pacific Tsunami Warning Centre (PTWC) tide
gauges in the Indian Ocean recorded minor wave activity in the
Australian Cocos Island (4-9 inches), the Maldives (6-inches) and
Sri Lanka (10-12-inches).
There
were reports of the sea receeding at several places
along the coast of Chennai, Mamalapuram and Tuticorin in Tamil Nadu
and Machilipatnam in Andhra Pradesh in India.
Thousands of people in India, Indonesia, Malaysia, Sri Lanka and
Thailand were either evacuated to safer places or fled of their on
accord to higher grounds. In Sumatra, roads leading out of Banda
Aceh were jammed with vehicles and people trying to flee the city.
Similar scenes were repeated across the region. In Sri Lanka,
residents of Colombo, Trincomalee and other coastal areas were
advised to more away from the coast as a precaution. At least 5 deaths were reported from Sri Lanka. These were
the result of road accidents or heart attacks due to panic driven
escapes by the population to higher ground at places such as Mavadippalli
and Kalmunai.
Hundreds of people fled to higher ground at places such as Batticaloa
and Vadamaradhhi East. The residents of the Maldives were also
advised to remain on alert for possible tsunami activity. In India,
the Andaman & Nicobar Islands and the coastal areas of the mainland
states of Andhra Pradesh, Kerala, the Lakshadweep Islands,
Pondicherry and Tamil Nadu were alerted. In Chennai, roads leading
to beachfront areas including the Marina Beach were cordoned of. In Thailand, many people immediately moved to higher ground in
places such as Khao Lhak, Koh Phi Phi, Krabi, Patong Beach, Phang
Nga, Phuket, Satun, and Takua Pa, Trang and similar scenes were
witnessed at Kedah, Langkawi, Penang & Perlis in Malaysia.
Alerts were issued in countries as far as Kenya and Madagascar in
east Africa and in the island nation of Mauritius. |
