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A great
earthquake (red star) struck the southern
Mentawai Strait and adjoining parts of
Bengkulu province, Sumatra on 12
September 2007 at 18:10
PM local time in Sumatra, Indonesia
causing damage, casualties and generating tsunami.
It had a magnitude of
Mw=8.4 and
tsunami warnings & watches were issued for the Indian Ocean
basin in its wake. The earthquake was
felt over a wide region of the western Indonesian archipelago,
parts of the Indo-China peninsula and even as far west as Male in
the Maldive Islands. This main earthquake (red star) was followed
the next day by two large
earthquakes of
Mw=7.9 (pink star) at 06:49 AM
local time and Mw=7.0 (yellow star) at 10:35 AM local time. Both were strongly felt in the region and resulted in
protracted tsunami warnings for Australia, Indonesia, Malaysia,
Singapore and Thailand.
Secondary
Event :
13 Sep 2007, Mw=7.9 South Mentawai-West
Bengkulu Earthquake
The earthquake was
centred 127 kms NW of Barhau (Enggano
Island), Indonesia,
129 kms SW of Bengkulu (Sumatra),
Indonesia,
134 kms SW of Lais (Sumatra), Indonesia
173 kms W of Manna (Sumatra), Indonesia,
183 kms SE of Tiop (Pangai Selatan), Indonesia,
218 kms S of Mukomuko (Sumatra), Indonesia,
448 kms WNW of Tanjung Telukbetong (Sumatra), Indonesia,
637 kilometres WNW
of Jakarta (Java), Indonesia,
719 kms SSW of Changi International
Airport, Singapore,
769 kms SE of Gunungsitoli (Nias Island), Indonesia,
1320 kms SE of Banda Aceh (Sumatra), Indonesia,
2706 kms SE of Sri Jayawardanepura-Kotte (Western Province), Sri
Lanka,
3054 kms SE of Chennai (Tamil Nadu), India,
3257 kms ESE of Male,
Maldives.
The first Mw=8.4 event is the strongest
earthquake off Sumatra since March 2005 and the strongest in this
immediate region since the June 2000 earthquake.
Two powerful earthquakes of Mw=7.9 and Mw=7.0 occurred within
24-hours of this Mw=8.4 event, the larger of the two presumably a
separate earthquake in itself and not an aftershock.
At least 25 people
died and
119 injured in this earthquake. It was strongly felt at Tuapejat
in the Mentawai Islands. According to the National Co-ordination
Board for Disaster Management at least 88,496 buildings suffered
damage of varying degrees out of which 17,965 were destroyed
Bengkulu & Sumatera Barat provinces. Scores of houses were heavily damage
or had cracks in their walls in the North and South Pagai Islands
in the Mentawai Islands Regency. Buildings have collapsed at Bengkulu,
Mukomuko
and Padang on Sumatra. The hospital at Bengkulu sustained damage
and was unable to provide services. The airport suffered minor
damage but was still operational after the quake. Fires were also reported from the city of Padang
at a mall as well as at several private residences. During
the earthquake in the city, parked cars were seen shaking and the ground seen
moving "up
and down". Damage was also reported from Bandar Lampung. The
earthquake was felt strongly at Jakarta on Java, sending many
people running outdoors. Tremors were experienced in the provinces of Bengkulu,
Lampung, Riau, Sumatera Uttara and Sumatera Barat. It was also felt in central Java. Power failures and disruption of
communications facilities were reported from Sumatra,
Indonesia.
Elsewhere in the
region, tremors were felt in many parts of Malaysia. In the
southern city of Johor Bahru it was felt at Banda Hilir, Bukit Cagar, Bukit
Saujana, Gelang Patah, Taman Desa Cemerlang and Ujong Pasir. It was also felt
at Putrajaya and in the capital, Kuala Lumpur, it was felt at
Cheras, Jalan Duta, Jalang Klang Lama, Jalan Pudu, Kepong, Padan Jaya, Petaling Jaya
and Setapak sending people running out of tall buildings
including the Petronas Towers. Minor cracks developed in
residential quarters of the Hospital Kuala Lumpur. At Melaka/Malacca, it was felt at Bukit
Beruang, Bukit Serangit and Taman Melaka Raya. Tremors were also
felt at Penang & Petaling Jaya.
Sink holes opened at three locations in Ipoh on the night of the
12th and Malaysian authorities did not rule out of the possibility
that they were related to this earthquake. In Singapore, the earthquake was felt in high-rise buildings
throughout the city. In the Central Business District (CBD) they
were felt at Battery Road, Market Street and Robinson Way. Many
officer workers evacuated into the streets causing traffic jams in
many areas. In an isolated instance, a "rock" fell from the
Robinson Tower in the CBD. Elsewhere in the nation state, it was
felt at Marsiling, Novena, Paris Ris, Potong Pasir Avenue, Raffles
Place, Toa Payoh and Thomson road. In Thailand, the shock was felt
as far as Bangkok & in one instance, a seismic seiche was
generated in the Saen Saeb Canal in the city. People ran out of
high-rise buildings at Silom, Sathorn and Ratchadaphisek in the
city. The earthquake was
also felt more than 3,200 kilometres to the west in high-rise
buildings in Male in the Maldives with residents in some cases
stating glasses on tables fell during the tremors.
A tsunami was
generated by this earthquake and was recorded at several locations
in the Indian Ocean. The tsunami propagated along the Indian Ocean
coast of Sumatra and Java reaching Sabang at 13:19 GMT (wave
heights=WH= 0.16 metres) and Cilacap at 13:13 GMT (WH=0.52
metres). It also fanned out into the Indian Ocean, arriving at the
Australian Cocos Islands at 12:28 GMT (WH=0.24m), Ko Taphao Noi on
Phuket Island, Thailand at ~15:05 GMT (WH=0.08m), Trincomalee on
the east coast of Sri Lanka at 14:58 UTC (WH=0.6m), Colombo on the
west coast of Sri Lanka at 15:19 GMT (WH=0.6m), Diego Garcia in
the British administered BIOT at 15:20 GMT (WH=0.09m), at Male in
the Maldives at 15:31 GMT (WH=0.21m), Rodriguez Island in
Mauritius at 17:04 GMT (WH=1.14m), Port Larue in the Seychelles at
19:06 GMT (WH=0.4m), Salalah in Oman at 19:23 GMT (WH=1.31m) and
Masirah also in Oman at 20:53 GMT (WH=0.07m). It was also recorded
at Lamu in Kenya. The largest wave heights away from the Sumatra
coast were recorded on Rodriguez Island and at Salalah, Oman.
Tsunami warnings and
watches were issued for countries and territories in the Indian
Ocean basin including Australia, Bangladesh, Indonesia, India,
Kenya, Malaysia, Mauritius, Mozambique, Sri Lanka, South Africa,
Tanzania and Thailand only to be lifted after the emergency had
passed. In Sumatra, a 3-metre tsunami is believed to have struck
Bengkulu city and other parts of North Bengkulu disitrict. A
tsunami also struck Muara Maras, Serangai and Urai in north
Bengkulu district to the north of Bengkulu causing damage to
several buildings. At Muara Maras, residents described the
recession of the sea followed by a tidal surge. Tidal flooding was
also reported from villages to the south of Bengkulu. "Waist deep"
flooding was reported from the Pagai Islands in the southern
Mentawai Island chain off the Bengkulu coast.
In India, alerts were
issued throughout the Andaman & Nicobar Islands as well as on the
mainland on all east coast states of Andhra Pradesh (eg. East
Godavari, Nellore, Ongole & Rajamundhry), Orissa (Balasore to
Ganjam), Tamil Nadu (eg. Chennai, Kanyakumari, Nagapattinam,
Ramanathapuram, Tirunelveli, Tuticorin) & West Bengal
(24-Parganas, East & West Midnapur) as well as Kerala (eg.
Thiruvananthapuram) and Karnataka (eg. Mangalore & Udupi) on the
west coast. At Chennai in Tamil Nadu, Marina Beach and the
Foreshore estate areas that were hard hit in December 2004 were
evacuated. In Sri Lanka, people evacuated to safer places at
Ampara, Batticaloa, Colombo, Dehiwala, Galle, Jaffna and
Killinochi among other places. Outside Galle, the Ruhunu Kumari
train was stopped halfway through its journey, passengers being
asked to disembark and were taken to the upper floor of the
district secretariat and patients were also moved from the
Mahamodara Hospital that was damaged in December 2004. At Colombo,
worshippers at the Bambalapitiya Mosque were evacuated as well. A
few traffic minor accidents were reported on the Galle-Matara road
as a result of panic that gripped the area. And in a few
potentially dangerous instances, people gathered along the
coastline to watch for any unusual activity in the sea. In
Bangladesh, loudspeakers alerted people and were then evacuated
schools, colleges & cyclone shelters at Cox's Bazaar, Pataukhali (Galachipa,
Kalapara & Kuakuta upazilas) as well as on Sandwip. Ships were
asked to return to port at Chittagong. In Myanmar, residents of
Maungdaw, Sittwe and other towns in the Rakhine State on the
Arakan coast fled to higher ground when news spread about the
possibility of a tsunami. Memories of the widespread
reach of the 2004 ocean-wide tsunami sparked concern as far as the
coast of Africa. In Tanzania, night sea
journeys were suspended, ferry services between Dar Es Salaam and
Zanzibar were delayed for several hours and public places along Mbezi Beach were closed.
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