Acehtsunami

The following is a release by the United States Geological Survey, National Earthquake Information Center: An earthquake occurred 70 km (40 miles) W of Tanaga Volcano, Alaska, 75 km (45 miles) N of Amatignak Island, Alaska, 2055 km (1270 miles) WSW of Anchorage, Alaska at 10:54 PM MST, Apr 15, 2008 (7:54 PM AHST in Aleutian Islands). The magnitude and location may be revised when additional data and further analysis results are available. This earthquake is located in a remote area and no damage or casualties are expected.

Distances : * 175 km (108 miles) W (271°) from Adak, AK
* 342 km (212 miles) W (266°) from Atka, AK
* 2054 km (1276 miles) WSW (253°) from Anchorage, AK

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.

The following is a release by the United States Geological Survey, National Earthquake Information Center: An earthquake occurred 225 km (140 miles) ESE of Visokoi Island, South Sandwich Islands at 8:57 AM MST, Feb 23, 2008 (1:57 PM local time in South Sandwich Is.). The magnitude and location may be revised when additional data and further analysis results are available. There have been no reports of damage. The magnitude was furnished by the G.S. Depth 10 km (6.2 miles) set by location program.

The following is a release by the United States Geological Survey, National Earthquake Information Center: An earthquake occurred 15 km (10 miles) ESE of Wells, Nevada 15 km (10 miles) ESE of Wells, Nevada at 7:16 AM MST, Feb 21, 2008 (6:16 AM PST in Nevada). The magnitude and location may be revised when additional data and further analysis results are available.

Felt Reports

At least three people injured and over twenty buildings heavily damaged and almost seven hundred buildings slightly damaged (VI) at Wells, Nevada. Felt (V) at Jackpot; (IV) at Battle Mountain, Carlin, Elko, Mountain City and Spring Creek; (III) at Ely, Eureka, Golconda, Lovelock and Winnemucca; (II) at Fallon and Reno, Nevada; (V) at Grand View and Rogerson; (IV) at Castleford, Filer, Hansen, Heyburn, Malad City, Malta, Paul, Rupert, Twin Falls and Wendell, (III) at American Falls, Bellevue, Boise, Buhl, Burley, Caldwell, Declo, Dietrich, Emmett, Fairfield, Garden Valley, Glenns Ferry, Gooding, Hagerman, Hailey, Hazelton, Idaho City, Inkom, Jerome, Ketchum, Kimberly, Middleton, Murtaugh, Nampa, Pocatello and Shoshone, (II) at Eagle, Garden City, Idaho Falls, Kellogg, Kuna, Lava Hot Springs, Mccammon, Meridian, Mountain Home, Preston and Star, Idaho; (V) at Wendover, (IV) at Farmington, Garland Salt Lake City and Snowville, (III) at American Fork, Brigham City, Clearfield, Corinne, Draper, Dugway, Grantsville, Hill AFB, Honeyville, Hooper, Hyde Park, Hyrum, Layton, Lehi, Logan, Ogden, Plymouth, Provo, Richmond, Roy, Sandy, Stockton, Syracuse, Tooele, Tremonton and West Jordan, (II) at Alpine, Bountiful, Delta, Kaysville, Lewiston, Magna, Midvale, North Salt Lake, Orem, Park City, Pleasant Grove, Providence, Riverton, Smithfield, South Jordan, Wellsville and Woods Cross, Utah; (II) at Spokane, Washington. Also felt at Laveen, Phoenix and Tucson, Arizona; Carmel Valley, Citrus Heights, Fort Bragg, Fresno, Huntington Beach, Midway City, Modesto, Newcastle, Oakland, Orange, Pasadena, Redwood City, Rocklin, Sacramento, San Ramon, Stockton and Ontario, California; Brighton and Fruita, Colorado; Aberdeen, Arco, Arimo, Bliss, Eden, Fish Haven, Greenleaf, Hammett, Homedale, Howe, Idaho Falls, Letha, Lucile, Mccall, Montpelier, Mountain Home A F B, Mullan, Murphy, New Plymouth, Paris, Parma, Pinehurst, Rockland, Soda Springs, Weiser, Weston and Wilder, Idaho; Absarokee, Montana; Albuquerque, New Mexico; Baker, Crescent Valley, Deeth, Denio, Fernley, Henderson, Nellis AFB, Overton, Pioche, Round Mountain, Tonopah and Yerington, Nevada; Burns, Harper, Jordan Valley, Nyssa and Ontario, Oregon; Bingham Canyon, Cedar Valley, Centerville, Clarkston, Cornish, Dutch John, Eden, Fielding, Grouse Creek, Hinckley, Huntsville, Lindon, Mendon, Mona, Morgan, Orem, Park, City, Payson, Portage, Rush Valley, Salem, Spanish Fork, Springville, Talmage, Vernon, Willard, Utah; Afton and Rock Springs, Wyoming.

Tectonic Summary

Seismological data from this earthquake show that it occurred on a normal fault that trends roughly north-south and has a dip of 30-60 degrees. The revised location of the mainshock puts the earthquake in the area northeast of Wells, Nevada, where geologically young faulting is poorly expressed. The USGS Quaternary Faults and Folds Database describes a network of widely distributed faults west of Wells Peak. Based on the revised location, the distribution of several aftershocks, and the depth of the mainshock, it is difficult to associate the earthquake with a specific fault.

A significant fault in the region that shows evidence of geologically young movement is the 64-km-long Independence Valley fault zone, which bounds the western side of the Pequop Mountains, but it is located more than 20 km southeast of the revised epicentral location and was probably not the source of the earthquake.

Earthquakes in Nevada are not uncommon. One of the most significant sequences of earthquakes in the western U.S. occurred in Nevada during the first half of the 20th century. The sequence started in 1915, when a magnitude 7.1 earthquake occurred in Pleasant Valley south of Winnemucca. The sequence culminated with a series of four major earthquakes that ranged in magnitude between 6.6 to 7.1 in 1954 the vicinity of the Carson Sink and Dixie Valley. This sequence of earthquakes defines the Central Nevada Seismic Belt.

The following is a release by the United States Geological Survey, National Earthquake Information Center: An earthquake occurred 310 km (195 miles) SSE of Banda Aceh, Sumatra, Indonesia, 310 km (195 miles) WSW of Medan, Sumatra, Indonesia, 335 km (210 miles) WNW of Sibolga, Sumatra, Indonesia, 1545 km (960 miles) NW of JAKARTA, Java, Indonesia at 1:08 AM MST, Feb 20, 2008 (3:08 PM local time in Indonesia). The magnitude and location may be revised when additional data and further analysis results are available. Earthquakes of this type sometimes cause tsunamis, however the USGS has no information that an actual tsunami has been generated.

Felt Reports

Three people killed and 25 seriously injured in the western Aceh province. Felt (V) at Meulaboh; (IV) at Banda Aceh, Medan and Tapaktuan; (III) at Gunungsitoli, Padang and Sibolga; (II) at Payakumbuh and Bukittinggi. Also felt at Duri and Lhokseumawe. Felt (III) at Butterworth, Gelugor, George Town, Kuala Lumpur, Petaling Jaya, Sungai Ara and Tanjong Tokong and (II) at Perai. Also felt at Alor Setar, Ayer Itam, Juru, Kajang-Sungai Chua, Kampong Tanjong Bunga, Kampong Tanjung Karang, Klang, Kota Baharu, Kuah, Kulim, Nibung Tepal and Shah Alam, Malaysia. Also felt at Kathu, Thailand.

Tectonic Summary

The magnitude 7.4 Simeulue, Indonesia earthquake of February 20, 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 55 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 occurred at the south end of the rupture zone of the great magnitude 9.1 earthquake of December 26, 2004 and at the north end of the rupture zone of the magnitude 8.6 Nias Island earthquake of March 28, 2005, where the 2004 and 2005 rupture zones nearly abut. The earthquake of December 26, 2004, produced the devastating Indian Ocean tsunami of that date. Since 2000, much of the Sunda trench between the northern Andaman Islands to Eggano Island, a distance of more than 2,000 km, has ruptured in a series of large subduction zone earthquakes.

The following is a release by the United States Geological Survey, National Earthquake Information Center: An earthquake occurred 55 km (35 miles) SSW of Kalamata, Greece and 230 km (145 miles) SW of ATHENS, Greece at 3:09 AM MST, Feb 14, 2008 (12:09 PM local time in Greece). The magnitude and location may be revised when additional data and further analysis results are available. There have been no reports of damage.