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2020-10-19, M7.5, Alaska

At 20:54:40 (UTC) on the 19th of October 2020, a magnitude 7.5 earthquake occurred near the Alaska Peninsula (see map below). The earthquake struck approximately 90 km south of the peninsula at a depth of 40 km. Initially a tsunami threat warning was issued by the Pacific Tsunami Warning Center, however it is now thought this threat has passed. The Alaska Peninsula is prone to large earthquakes due to the subduction of the Pacific plate beneath the North American plate in that region.

Location of the M7.5 Alaska earthquake.

The earthquake was recorded at seismic stations worldwide, including stations of the Irish Nation Seismic Network (INSN), see seismic waveforms below.

Seismic waveforms recorded by the INSN (click to enlarge).

Further information is available from the following sources:

https://earthquake.usgs.gov/earthquakes/eventpage/us6000c9hg/executive?utm_medium=email&utm_source=ENS&utm_campaign=realtime

https://www.emsc-csem.org/Earthquake/earthquake.php?id=912660

2020-07-22, M7.8, Alaska Peninsula

At 06:12:44 (UTC) on the 22nd of July 2020, a magnitude 7.8 earthquake occurred  near the Alaska Peninsula (see map below). The earthquake struck approximately 100 km south of the peninsula at a depth of 30 km. Shortly after, a tsunami warning was issued by the U.S. Tsunami Warning System. Several aftershocks of magnitude 5 and greater occurred within the hours following the main shock. Large earthquakes are common in this region due to the subduction of the Pacific plate beneath the North American plate. Since 1900, twelve earthquakes with magnitudes greater than 7.5 have occurred in this region, including the 1964 M9.2 Prince William Sound earthquake, the second largest recorded earthquake in the era of modern instrumental seismology.

The earthquake was recorded at seismic stations worldwide, including stations of the Irish Nation Seismic Network (INSN), see seismic waveforms below (select figure to enlarge).

Further information is available from the following sources:

https://www.emsc-csem.org/Earthquake/earthquake.php?id=878808

https://earthquake.usgs.gov/earthquakes/eventpage/us7000asvb/executive

Past Seismograms
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Live Seismograms
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Past Spectrograms
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Live Spectrograms
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ITIP - N. Tipperary
IMAY - Mayo