Alaska quake center series#

This broad zone of seismicity includes a series of predominantly thrust faults, and a 1943 M7.0 earthquake may have originated in this band. The diffuse zone of seismicity between Cook Inlet and the Denali Fault may mark a deformation zone between the Bering microplate to the west and the southern Alaska block to the east. The Castle Mountain Fault, which passes 25 miles (40 km) north of Anchorage, exhibits geological evidence of Holocene offsets and generated the 1984 M5.6 Sutton Earthquake. The April 1933 M6.9 earthquake, which caused considerable damage in Anchorage, appears to have occurred on such a structure. Mapped geological structures in upper Cook Inlet are capable of generating strong earthquakes. (3) Crustal seismicity in this region can be attributed to three major sources: the faults and folds of the Cook Inlet basin, the Castle Mountain Fault, and the wide band of diffuse seismicity extending from northern Cook Inlet to the Denali Fault. Both produced significant ground shaking in the Southcentral region and resulted in structural damage to buildings and infrastructure.

The 2016 M7.1 Iniskin and the 2018 M7.1 Anchorage earthquakes are the most recent notable intermediate-depth events. In southern and central Alaska, this seismicity abates at a depth of approximately 140 miles (225 km), reflecting the down-dip extension of the Pacific Plate. This zone extends along the Aleutian Arc, Alaska Peninsula, and Cook Inlet and terminates beneath the northern foothills of the Alaska Range. (2) Intermediate-depth seismicity (below 20 miles/32 km) occurs in the Wadati-Benioff Zone, where the subducting Pacific Plate descends towards the mantle beneath the North American Plate. The 1964 M9.2 Great Alaska Earthquake, which is still the second largest earthquake ever recorded worldwide, originated under Prince William Sound. (1) The strongest earthquakes in Southcentral Alaska are generated by the megathrust fault that marks the contact zone between the subducting Pacific and overriding North American plates. All rights reserved.Tectonic Setting of Southern AlaskaEarthquakes in Southcentral Alaska are produced by a number of different tectonic features. That would be a highly destructive, and damaging, and potentially deadly event.”Ĭopyright 2021 KTVF. They don’t happen very often, perhaps not in our lifetime, perhaps next month - and an earthquake of that size today, we would be talking about very different things right now had that earthquake occurred. However, we know that the Salcha Seismic Zone is capable of earthquakes like that. Fairbanks was a different place of course in 1937.

USGS Magnitude 2.5+ Earthquakes, Past Day 26 earthquakes. “That’s an earthquake that had tremendous impacts on the surface of the earth - you know, big cracks, fault lines, it had violent shaking across the Fairbanks region. If the application does not load, try our legacy Latest Earthquakes application. One of the reasons we pay attention to this area, and that it’s on the radar so to speak, is that it’s not far from the location of the 1937 earthquake which was in excess of magnitude seven” West continued.

So I think it’s safe to say that we’ll be keeping an eye on that area over the next few months.”Īnd along with July’s earthquake, historically, there is precedent for much larger quakes in the same area. But it does catch our attention that we’ve had two of them, and this is an area where we know that historically, much larger earthquakes are possible. “Two earthquakes do not create, you know, a sequence or series or something. “One of the things that has our attention, is that this earthquake occurred more or less in the same place as a almost as large earthquake back in July,” West said. There’s a geologic feature of some sort that is prone to creating these quakes.”īut what caught the eye of the Alaska Earthquake center was this quake’s proximity to another. If you take the location of all the historical earthquakes, there’s a feature there. They, rather, fall along a very well defined delineation. “We call it that because there’s a history of earthquakes here and they are not randomly scattered around. “The location of this earthquake is not a surprise, it happened in an area that we refer to loosely as the Salcha Seismic Zone,” West explained.

Alaska quake center