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2022-03-16, M7.3, Japan
At 14:36:33 (UTC) on the 16th of March 2022 a magnitude 7.3 earthquake occurred near the east coast of Honshu Japan, 57 km east-north-east of Namie which is located in Fukushima Prefecture (see map below). The NWS Pacific Tsunami Warning Center initially issued a warning for hazardous waves along the coast of Japan but now reports the threat from this event has passed. The Tokyo Electric Power Company reports over 2 million households in nine prefectures have been left without electricity due to the earthquake.
Japans tectonic setting is complex as it is influenced by the North America plate, Pacific plate, Philippine Sea plate, and Eurasian plate. A detailed summary of the region is available from the USGS at the following link https://earthquake.usgs.gov/earthquakes/eventpage/us6000h519/region-info.
The event was recorded by seismic stations worldwide, including stations in the Irish National Seismic Network (INSN) (see figure below). The first seismic waves originating from the Japan earthquake arrived in Ireland ~15 minutes after the event origin.
For more information on the M7.3 Japan earthquake please see these links:
https://www.jma.go.jp/bosai/map.html#5/38.393/143.174/&elem=warn&contents=tsunami&lang=en
http://geofon.gfz-potsdam.de/eqinfo/event.php?id=gfz2022fgid
https://www.emsc-csem.org/Earthquake/earthquake.php?id=1107417
2022-01-15, Eruption in Tonga
The underwater volcano “Hunga Tonga-Hunga Ha’apai” in Tonga has been experiencing ongoing volcanic activity since the 20th December 2021. From the 5th of January 2022 activity had decreased, but on the 15th it increased again with a large eruption occurring with a sonic boom that was heard hundreds of kms away. The event was recorded by seismic stations worldwide, including stations in the Irish National Seismic Network (INSN) (see figure below). The first signals originating from the Tonga event arrived ~15 hours after the event origin. A large plume of ash was visible on satellite images and the eruption was heard in Tonga, the surrounding islands and with reports from as far away as Alaska. The eruption also generated a tidal wave warning for the Pacific region.
2021-11-16, M3.3, Scotland
On the 16th of November 2021 at 01:44 UTC a magnitude 3.3 earthquake occurred in Western Scotland. The earthquake located with a depth of approximately 6 km and is indicated by the red circle in the map below. There have been reports of the event being felt in Scotland and Northern Ireland.
The event was recorded by the stations of the Irish National Seismic Network (INSN) and can be seen in the waveforms plotted below:
Listen to Dr Martin Möllhoff discussing this event on RTE Radio 1’s Morning Ireland show here:
https://www.rte.ie/radio/radio1/clips/22030318/
More information is available from:
https://earthquake.usgs.gov/earthquakes/eventpage/us7000fugg/executive
https://www.emsc.eu/Earthquake/earthquake.php?id=1062853
http://www.earthquakes.bgs.ac.uk/earthquakes/recent_events/20211116014340.html#page=summary
2021-07-29, M8.2, Alaska
On July 29, 2021 at 06:15 UTC (July 28, 2021 22:51 local time) a magnitude 8.2 earthquake occurred approximately 80km south of the Alaska Penninsula (see map below). The USGS report the earthquake originated at a depth of 32 kilometers. Large earthquakes are common in this region as a result of thrust faulting at shallow depth on the subduction zone interface between the Pacific plate and the North America plate.
The event was recorded by seismic stations worldwide, including stations in the Irish National Seismic Network (INSN) (see figure below). The first seismic waves originating from the Alaska earthquake arrived ~6 minutes after the event origin.
For more information please see the links below:
https://www.usgs.gov/news/magnitude-82-earthquake-alaska
https://www.emsc-csem.org/Earthquake/earthquake.php?id=1014588
2021-03-04, M8.1, Kermadec Islands
At 19:28 on the 4th March 2021 a magnitude 8.1 earthquake occurred in the Kermadec Islands region. This follows two other strong events in the region today, an M7.3 event which occurred further south close to the North Island of New Zealand (see here) and an M7.4 event that also occurred in the Kermadec Islands region (see here).
New Zealands National Emergency Management Agency (NEMA) have issued a statement advising people on the east coast of the north island to move to higher ground. The earthquake had a depth of 10 km, shallow earthquakes like this present a tsunami threat.
The event was recorded by seismic stations worldwide, including stations in the Irish Nation Seismic Network (INSN) (see figure below).
The earthquake occurred along the eastern margin of the Australia plate where it meets the Pacific plate. The convergence of the two plates means the region is prone to large events such as this (there have been 15 earthquakes with magnitude greater than 7.5 since 1900).
For more information see the following:
https://earthquake.usgs.gov/earthquakes/eventpage/us7000dflf/executive
https://www.emsc-csem.org/Earthquake/earthquake.php?id=955088
2021-03-04, M7.3, New Zealand
At 13:27 on 4th March 2021 a magnitude 7.3 earthquake occurred off the East coast of the New Zealand’s Northern Island (see map below). The Pacific Tsunami Warning Center (PTWC) immediately issued a warning for the possibility of hazardous Tsunami waves within 300 km of the earthquake epicenter along the New Zealand coast. Tsunami waves of 0.28 m were then observed on the Northeastern Cape and waves of 0.3 to 3 m have been forecast.
The event was recorded by seismic stations worldwide. The stations in the Irish Nation Seismic Network (INSN), recorded it approximately 20 minutes after it occurred (see figure below).
New Zealand is on the Eastern margin of the Australian plate and the region is prone to large events such as this (there have been 15 earthquakes with magnitude greater than 7.5 since 1900). The convergence of the Australia and Pacific plates make it one of the most seismically active areas in the world.
For more information see the following:
https://earthquake.usgs.gov/earthquakes/eventpage/us7000dffl/executive
https://www.geonet.org.nz/earthquake/2021p169083
https://www.emsc-csem.org/Earthquake/earthquake.php?id=954885
2021-02-24, M5.7, Iceland
The Reykjanes Peninsula in Iceland has suffered a series of earthquakes in the past few hours. This phenomena is known as an earthquake swarm. At the time of writing, there have been 725 quakes in the last 48 hours. The largest of which was a magnitude 5.7 that occurred at 10:05:57 on the 24th February 2021. This event was recorded by the Irish National Seismic Network and can be seen in the waveforms plotted below.
More information is available from the Icelandic Met Office:
https://en.vedur.is/about-imo/news/earthquake-swarm-in-reykjanes-peninsula
and on this webpage:
https://www.ruv.is/frett/2021/02/24/earthquake-alert-level-increased
present earthquake activity on the Reykjanes peninsula is shown here:
https://en.vedur.is/earthquakes-and-volcanism/earthquakes/reykjanespeninsula#view=map
2020-10-30, M7.0, Greece
At 11:51:26 (UTC) on the 30th of October 2020, a magnitude 7.0 earthquake occurred 14 km NE of Néon Karlovásion, Greece (see map below). Early reports state that there has been building collapse and a sea surge that flooded streets in the Turkish resort city of Izmir. The Mediterranean region is prone to such events due to the northward convergence of the African plate with respect to the Eurasian plate along a complex plate boundary.
The earthquake was recorded at seismic stations worldwide, including stations of the Irish Nation Seismic Network (INSN), see seismic waveforms below.
Further information is available from the following sources:
https://earthquake.usgs.gov/earthquakes/eventpage/us7000c7y0/executive
https://www.emsc-csem.org/Earthquake/earthquake.php?id=915787
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.
The earthquake was recorded at seismic stations worldwide, including stations of the Irish Nation Seismic Network (INSN), see seismic waveforms below.
Further information is available from the following sources:
https://www.emsc-csem.org/Earthquake/earthquake.php?id=912660
2020-06-23, M7.4, Oaxaca, Mexico
At 15:29:05 (Universal Time) on the 23rd of June 2020, an earthquake of magnitude 7.4 struck in the Oaxaca region of Mexico (see map below). The earthquake occurred at a depth of 10 km, locating approximately 12 km SSW of Santa Maria Zapotitlan, Mexico. Shortly after, the Pacific Tsunami Warning Canter (PTWC) issued a warning that hazardous tsunami waves reaching 1 to 3 m above the tide level along the coast of Mexico are possible.
Mexico is one the earths most seismically active regions due to the relative motions of three large tectonic plates (the Pacific Plate, the Cocos Plate and the North American Plate) in the region. The relatively dense oceanic crust of the pacific plate is subducting beneath the Mexican landmass. This motion can result in large earthquakes such as today’s event. The interaction of the subducting plate and the mantel rock beneath the Mexican landmass also results in volcanism in the area.
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=870434