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2018-11-30, M7.0, Southern Alaska

An earthquake of magnitude 7.0 occurred in Southern Alaska, on the 30th November 2018 at 8:29 a.m. local time (17:29:28 UTC). The quake was centred about 11km north of Anchorage, the largest city in the state, according to the US Geological Survey (USGS). A series of aftershocks was recorded following the initial shock, which had a depth of 40.9km, the USGS said. Around 300,000 people live in Anchorage with 100,000 in the surrounding area. A tsunami warning issued for the Cook Inlet and southern Kenai Peninsula regions was later cancelled.

This earthquake occurred in the Alaska-Aleutian subduction zone, on a fault within the subducting Pacific slab.

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

2018-02-17, M4.4 South Wales

On the 17th February 2018 an earthquake with magnitude 4.4 occurred at 14:31:07.6 UTC at a depth of 7.4km in South Wales about 20km north of Swansea, see map below. According to the BGS  hundreds of members of the public submitted felt reports. Events of this magnitude happen in the UK only about every 2 to 3 years. The BGS reports that this is the biggest event in the area since a magnitude 5.2 earthquake in 1906.

dias2018dizj-map-no_stations-05deg
The earthquake was recorded at stations of the Irish National Seismic Network (INSN), see seismic waveforms below (select figure to enlarge).

4-4_2018-02-17_048_14-31-10-800_52-11-5-49_3_240_0_2-none-ei-none

Further information about this event is available from the following webpages:

BGS: http://earthquakes.bgs.ac.uk/earthquakes/recent_events/20180217142554.html#page=summary

EMSC: https://www.emsc-csem.org/Earthquake/earthquake.php?id=649041
GFZ: http://geofon.gfz-potsdam.de/eqinfo/event.php?id=gfz2018dizj

The drumplot below shows the unfiltered seismic signal recorded on the 17th February 2017 at INSN station DSB in the Dublin mountains. The high amplitude low frequency signals between midnight and 1 a.m. are the surface waves of the M7.2 Mexico earthquake that occurred on the 16th February 2018 at 23:39:39, see https://www.insn.ie/2017-02-16-m7-2-mexico for more details on that event. The magnitude 4.4 event with epicentre in South Wales can be seen with much higher frequency content around 14:32.

ei-dsb-hhz-d-2018-048-drum-17-02

More information about the INSN is available via this link.

2017-08-02, M1.5 Donegal

On the 2nd August at 05:46 UTC (06:46 local time) an earthquake of magnitude 1.5 occurred in Donegal (NE of Milford on the Fanad Peninsula). Location 55.11N, 7.59W, see figure below.

There are reports of this event having been felt in the area around Milford. Events of this nature are not uncommon in this region. The largest event recorded in this area was a magnitude 2.2 which occurred near Clonmany on 21st November 1994.

The event was recorded at stations of the Irish National Seismic Network (INSN) and the BGS, see seismic traces below.

2017-05-18, M1.3 Irish Sea

An earthquake with magnitude ML 1.3 occurred on the 18th May 2017 at 23:04:12 UTC in the Irish Sea. The epicentral location of this event is 53.05N, 5.49 W, about 40km off the Wicklow coast, see map below.

The earthquake was detected by seismic stations of the Irish National Seismic Network (INSN) and the British Geological Survey (BGS), see seismograms below.

The epicentre is close to the location where a similar earthquake with magnitude ML 0.9 occurred on the 10th March 2017, see here for more information. Real-time information of automatic INSN event detections can be accessed  on the INSN homepage at https://www.insn.ie/events.

2017-03-10, M0.9 Irish Sea

On the 10th March 2017 at 05:06:25 UTC an earthquake of magnitude ML 0.9 occurred in the Irish Sea, approximately 50km off the coast of Wicklow, with the epicentral location 53.04N, 5.51W, see map below.

The event was recorded at Irish National Seismic Network (INSN) stations and at several British Geological Survey (BGS) stations in Wales and the Isle of Man, see seismograms below.

This earthquake was too weak to be felt by humans and occurred in a region of the Irish Sea for which several events have been detected in the past, see map on this INSN page.