Acehtsunami

The following is a release by the United States Geological Survey, National Earthquake Information Center: An earthquake occurred 85 km (55 miles) SSW of Isangel, Tanna, Vanuatu, 175 km (110 miles) NE of Tadine, Loyalty Islands, New Caledonia, 275 km (170 miles) S of PORT-VILA, Efate, Vanuatu, 1800 km (1120 miles) ENE of BRISBANE, Queensland, Australia at 5:46 AM MST, Apr 9, 2008 (11:46 PM local time in Loyalty Islands). The magnitude and location may be revised when additional data and further analysis results are available. No reports of damage or casualties have been received at this time.

75 km (45 miles) SW of Isangel, Tanna, Vanuatu
185 km (115 miles) NNE of Tadine, Loyalty Islands, New Caledonia
265 km (165 miles) SSE of PORT-VILA, Efate, Vanuatu
1800 km (1120 miles) ENE of BRISBANE, Queensland, Australia

The earthquake occurred as a result of normal faulting in the tectonically complex region of the northern Tibetan Plateau. This earthquake occurred several hundred kilometers north of the convergent India-Eurasia plate boundary, where the Indian Plate is moving northwards with respect to Eurasia at a rate of approximately 46 mm/yr. This convergence drives the uplift of the Himalaya Mountains, at a rate of approximately 10 mm/yr, and the Tibetan Plateau, which is an extremely broad region of thickened and uplifted crust sitting above 4.5-5.0 km.

The uplifted Tibetan Plateau is spreading to the east and, as a result, is an area of east-west extension and eastward crustal motion within a larger region of generally north-south convergence. The Xinjiang-Xizang earthquake likely reflects the interplay amongst these major tectonic forces, dominated in this location by east-west extension. The eastward motion of Tibet, with respect to Eurasia further north, is accommodated in part by the large intra-continental Altyn Tagh and Kunlun strike-slip fault systems. The March 20, 2008 event is one of the largest known historical earthquakes to have occurred in the northern Tibetan Plateau west of the Kunlun Fault System. In 1996, a 6.9Mw earthquake occurred approximately 300 km further west.

The following is a release by the United States Geological Survey, National Earthquake Information Center: An earthquake occurred about 175 km (110 mi) east-southeast of Pandan, Catanduanes at 7:11 AM MST, Mar 3, 2008 (10:11 PM local time in Philippines). The magnitude and location may be revised when additional data and further analysis results are available. No reports of damage or casualties have been received at this time; however, this earthquake may have caused damage due to its location and size.
Distances-175 km (110 miles) ESE of Pandan, Catanduanes, Philippines
180 km (110 miles) NE of Calbayog, Samar, Philippines
210 km (130 miles) E of Legaspi, Luzon, Philippines
525 km (325 miles) ESE of MANILA, Philippines

One person injured and damage to buildings in the Lincolnshire and South Yorkshire areas. Felt (V) at Barnsley, Bedworth, Beeston and Stapleford, Bentley, Beverley, Bicester, Boston, Brigg, Brighouse, Chesterfield, Chorley, Cleethorpes, Doncaster, Droitwich, East Retford, Eaton Socon-Saint Neots, Failsworth, Grantham, Grimsby, Heywood, Hinckley, Ilkeston, Kirby in Ashfield, Leicester, Lincoln, Long Eaton, Loughborough, Mablethorpe and Sutton, Matlock, Melton Mowbray, Mold, Morley, Oakham, Rotherham, Sheffield, Skegness, Sleaford, Spalding-Pinchbeck, Whitefield and Worksop. Felt widely in the United Kingdom, north to Arbroath, southwest to Falmouth-Penrynm and east to Great Yarmouth. Felt (II) at Gent, Belgium. Also felt at Douglas, Isle of Man; at Antwerp and Brussels, Belgium; and at Aniche, France.
Distances - 40 km (25 miles) S of Kingston upon Hull, England, UK
75 km (45 miles) NE of Nottingham, England, UK
80 km (50 miles) E of Sheffield, England, UK
210 km (130 miles) N of LONDON, United Kingdom

The following is a release by the United States Geological Survey, National Earthquake Information Center: An earthquake occurred 160 km (100 miles) SSW of Padang, Sumatra, Indonesia and 855 km (530 miles) WNW of JAKARTA, Java, Indonesia at 1:36 AM MST, Feb 25, 2008 (3:36 PM local time in Indonesia). The magnitude and location may be revised when additional data and further analysis results are available. There have been no reports of damage.

Felt Reports

WP 7.3 (HDRA). Felt (III) at Pekanbaru. Also felt at Curup, Duri and Padang. Felt (III) at Johor Bahru, Malaysia. Also felt at George Town, Malaysia. Felt (III) at Singapore, Singapore.

Tectonic Summary

The magnitude 7.0 Kepulauan Mentawai, Indonesia, earthquake of February 25, 2008 occurred as the result of thrust faulting on the boundary between the Australia and Sunda plates. At the location of this earthquake, the Australia plate moves north-northeast with respect to the Sunda plate at a velocity of about 60 mm/year. The direction of relative plate motion is oblique to the orientation of the plate boundary offshore of the west coast of Sumatra. The component of plate-motion perpendicular to the boundary is accommodated by thrust faulting on the offshore plate-boundary, with the Australia plate subducting beneath the Sunda plate. Much of the component of plate motion parallel to the plate boundary is accommodated by strike-skip faulting on the Sumatra fault, which is inland on Sumatra proper.

This earthquake continues an episode of unusually high earthquake activity that has impacted Sumatra and vicinity in recent years. Previous earthquakes in the series of shocks include the Sumatra-Andaman Islands earthquake of December 26, 2004 (M 9.1), the Nias earthquake of March 28, 2005 (M 8.6), and the southern Sumatra earthquakes of September 12, 2007 (M 8.4 and 7.9). The earthquake of February 25, 2008, occurred within the broad section of the Sumatra subduction zone that was spanned by aftershocks of the southern Sumatra earthquakes of September 12, 2007.