Three of the Sumatra earthquakes of September 2007 had a magnitude of 7 or above and were part of a series of megathrust quakes that hit the Sunda Trench off the coast of Sumatra, Indonesia. There were several tsunami warnings sent out for the region. With a magnitude of 8.4, the strongest in the series ranks among the top 20 largest earthquakes ever detected by a seismograph.

Shocks from the 8.4 Mw earthquake lasted for many minutes. As a result, structures in Jakarta started to sway, and some buildings in Bengkulu, in the province of Bengkulu, some 100 km away, reportedly crumbled. The earthquakes reported in Jakarta were referred to as "violent." According to reports, several high-rise buildings needed to be evacuated. The earthquake caused a power outage in Bengkulu, which significantly impeded communication. The earthquakes have resulted in 88 injuries and 21 fatalities.

Tremors were detected in close-by countries and as far away as Southern Thailand. At approximately 11:10 UTC, an earthquake was felt in Singapore, which is located 670 kilometers from the epicenter (19:10 local time). The tremor was felt throughout the bulk of Central and Eastern Singapore. After 19:15 local time, Peninsular Malaysia experienced tremors, according to reports from Kuala Lumpur, Putrajaya, Johor Bahru, Malacca, and Penang. Similar to Singapore, the strongest tremors were felt in high-rise structures, which caused a moment of panic and forced evacuations. No fatalities had been reported in the country as of September 13th. Data on sea level indicated that a tsunami had been produced. There were a total of 4 tsunami advisories in a 24-hour period.

Following the first and biggest earthquake, the Pacific Tsunami Warning Center issued a tsunami alert for much of the Indian Ocean basin. An estimated 1-meter-high tsunami was seen in Padang, Indonesia. A tsunami with a height of about 15 cm was seen at the Cocos Islands. The tsunami warning for Sumatra was canceled after two hours.

Tsunami alerts were also issued for India and other countries bordering the Indian Ocean not long after the earthquake. The Indian government issued alert levels for Tamil Nadu, Kerala, Andhra Pradesh, the union territories of the Andaman and Nicobar Islands, and Puducherry. By late on September 12, the tsunami warning had been lifted. Similar to this, a tsunami warning was issued for Peninsular Malaysia's coastal areas of Perlis, Kedah, Perak, and Penang about 20:50 (local time), and it was later lifted. Authorities in Malaysia had found a 1-3 m high wave that was departing from the site of the earthquake.

Source: WIKIPEDEA September 2007 Sumatra earthquakes

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