Alaska quake depth8/24/2023 Slip on the Denali fault peaked at 8.8 m (29 ft) with an average slip of 5.3 m (17 ft). Slip on the Susitna Glacier thrust peaked at 4 m (13 ft) with an average displacement of 1.4 m (4 ft 7 in) across the fault. The rupture then jumped to the main Denali Fault strand propagating for a further 218 km (135 mi) before jumping again onto the Totschunda Fault through a wide and complex transition zone, and then ruptured another 70 km (43 mi) of fault plane. The initial rupture on November 3, nucleating 22 km (14 mi) east of the foreshock, was on a thrust fault segment, the previously unknown Susitna Glacier thrust, to the south of the Denali fault. The calculated stress transfer from this foreshock indicates that it brought the Denali fault closer to failure at the location of the mainshock epicenter. Because of its location close to the November 3 event and the fact that it preceded it by only 11 days, this earthquake is regarded as a foreshock. Minor avalanches of snow and rockfalls were plenty in the area as a result. This rupture extends to 10 km (6.2 mi) west of the mainshock's epicenter. ![]() The event's aftershocks revealed a 45 km (28 mi) long fault rupture along the Denali fault, but aerial reconnaissance could not locate a surface rupture. On October 23, 2002, there was a magnitude 6.7 earthquake located on the Denali fault. The Denali-Totschunda fault system is one of the structures that accommodate the accretion of the Yakutat terrane. In Alaska, moving from east to west, the plate interactions change from a transform boundary between Pacific and North American plates to a collision zone with a microplate, the Yakutat terrane, which is in the process of being accreted to the North American plate, to a destructive boundary along the line of the Aleutian islands. The Denali-Totschunda fault is a major dextral (right lateral) strike-slip system, similar in scale to the San Andreas fault system. About 20 houseboats were damaged by a seiche on a lake in Washington State. Due to the remote location, there were no fatalities and only one injury.ĭue to the shallow depth, it was felt at least as far away as Seattle and it generated seiches on bodies of water as far away as Texas and New Orleans, Louisiana. The shock was the strongest ever recorded in the interior of Alaska. This 7.9 M w earthquake was the largest recorded in the United States in 37 years (after the 1965 Rat Islands earthquake). The 2002 Denali earthquake occurred at 22:12:41 UTC (1:12 PM Local Time) November 3 with an epicenter 66 km ESE of Denali National Park, Alaska, United States. One in October had a magnitude of 7.4, while another quake in July 2020 measured 7.6.Extent of surface rupture caused by faulting during the 2002 Denali earthquake The 1964 quake claimed the lives of more than 250 people, destroying Anchorage and unleashing a tsunami that wreaked havoc across the Gulf of Alaska.Īlaska was struck by two weaker earthquakes last year. An earthquake in Anchorage in 2018 caused significant damage Image: Reuters/N. ![]() The US state is part of the seismically active Pacific Ring of Fire where earthquakes are very common. Has Alaska been hit by earthquakes before?Īlaska was was hit by a 9.2-magnitude earthquake in March 1964, the strongest ever recorded in North America. When plates snap back into position, the energy from this movement can cause huge waves to form. Japanese public broadcaster NHK reported that there is no risk of tsunami damaging Japan's coast after it said there might be small changes to tide levels.Įarthquakes are the result of sudden movement along faults within the Earth caused by the release of built-up pressure at plate boundaries. Officials at the Pacific Tsunami Warning Center scrapped the alerts when it emerged that the threat was not as great as first feared. In Seward on the Kenai Peninsula, south of Anchorage, sirens blared as residents were ordered to move to higher ground. In Alaska, there were no immediate reports of injuries or damage. Several coastal communities had been evacuated as a precaution. But authorities later canceled those warnings. ![]() Tsunami warnings were issued for Alaska, Hawaii, and the Pacific territories of Guam and the Northern Mariana Islands. Image: Deutsche Welle (DW) Why were the tsunami warnings canceled? The earthquake hit 56 miles (91 kilometers) southeast of the town of Perryville, some 500 miles from Anchorage, Alaska's biggest city. It measured the quake as having a depth of 35 kilometers (21.7 miles). The US Geological Survey (USGS) had initially reported that the magnitude was 7.2. US authorities lifted a string of tsnuami warnings after an earthquake of magnitude 8.2 struck the Alaska Peninsula on Thursday.
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