Alaska Experiencing Two Sizable Earthquakes Leads to the Big One?

Alaska

Alaska recently experienced two sizable earthquakes within the last 48 hours of each other which may lead to the big one… or, maybe it will not. The first earthquake to occur in Alaska was along the Aleutian Islands on Sunday, July 26 and had a magnitude of around 6.9. The second one occurred on the night of July 28 near Redoubt Volcano and measured around 6.3.

Alaska is part of the Pacific Ring-of-Fire. It is no surprise, then, that sizable quakes ring throughout parts of Northern and Southern America, parts of Australia and Fiji, and Japan. In fact, two other earthquakes hit within this area on July 28 as well. One, which measured around 7.0, hit the Papua region in Indonesia. The other one measured around 5.9 and occurred off the coast near the Panama and Colombia Border. The area is not directly located within the Ring-of-Fire, per say, but could easily be impacted by it.

Recently, Kathryn Schulz of The New Yorker wrote about The Really Big One which is a potentially disastrous earthquake predicted by scientists to occur along the Cascadia subduction zone area located in the Pacific Northwest. Areas which may be heavily affected include the British Columbia area of Canada, Washington, Oregon, and parts of Northern California.

Schulz goes into detail about the devastation predicted by the Federal Emergency Management Agency (FEMA) if the really big one were to occur in that region, but it appears she did not elaborate on the really big one which had occurred in Alaska in the 1960s, nor a not so really big one which had occurred in 1868 along the Hayward Fault located in Northern California.

In fact, Alaska recently having experienced two sizable earthquakes may lead to an even bigger earthquake. After all, earthquakes appear to be stronger in most recent years and one may wonder if it is a sign that the Pacific region will soon face another great, devastating earthquake. The Pacific Ring-of-Fire is known to be quite shaky and active, but will it soon produce an earthquake in the Pacific Northwest similar to the one which occurred in Japan in 2011 and in Indonesia in 2004?

According to Schulz, the average time frame estimated by scientists for the really big one to recur along the Cascadia subduction zone is 243 years. Schulz admits that according to calculations, it has been 315 years since the last one hit that region. It was estimated to have occurred around the year 1700 with a magnitude of about 9.0.

Alaska

One of the largest recorded earthquakes to occur along the Pacific Ring-of-Fire took place in Alaska in 1964. It measured around 9.2 and had an epicenter in the Prince William Sound region. It occurred due to the Pacific Plate lurching northward and underneath the North American Plate. According to the U.S. Geological Survey (USGS), water recorders located as far away as Louisiana had registered the earthquake.

Schulz reported the Cascadia subduction zone consists of the Juan de Fuca Plate pushing eastward toward the North American Plate. Aside from this particular area, the infamous San Andreas Fault in California is well-known for producing strong surface earthquakes. This is because it has a strike-slip movement with the Pacific Plate moving laterally to the North American Plate. It can cause great damage from earthquakes of smaller magnitudes, as opposed to those created by subduction zone ones.

Although Schulz reported heavily on the scientific discovery of the Cascadia subduction zone area and earthquakes which may have caused large tsunamis that hit Japan, it would have been wise for her to include those which have been predicted to also strike in Alaska and California. These areas have been known to produce devastating earthquakes which can also affect thousands and cause enormous economic devastation.

In fact, scientists had reported in 2008 that a powerful earthquake had rattled the San Francisco Bay Area in 1868 and was originally thought to have been caused by the San Andreas Fault. It may have actually been caused by the Hayward Fault, which is located closer to Oakland and San Jose. It measured around 6.8 and caused buildings to collapse; though, according to USGS, the area was sparsely populated at the time.

Scientists stated in 2008 that the interval for the Hayward Fault to rupture appeared to be between 95 to 160 years, with an average of about 138 years. This, too, is a dire concern for scientists and government agencies given that devastation can occur with regards to impact on the population and economic activity for areas located near this fault line. Also, the year 2008 had marked the 140 year anniversary since the last time the Hayward Fault had made any significant movement.

Alaska recently experiencing two sizable earthquakes may be a foreshock leading to an even bigger one, or it simply may have been due to volcanic or normal seismic activity. Although the Pacific Northwest is predicted to be affected by a devastatingly enormous earthquake due to scientific estimates of the Cascadia subduction zone area, it would be wise for government agencies, businesses, and citizens to prepare for any probable impact occurring along any high-impact areas. This would include the need to allocate resources, practice drills, and access units, such as buildings and bridges, that should be up to code.

by Liz Pimentel

Read also Guardian Liberty Voice: Earthquakes May Be on the Rise

Sources:

The New Yorker – The Really Big One
USGS – The 1964 Great Alaska Earthquake and Tsunamis—A Modern Perspective and Enduring Legacies
USGS – The Hayward Fault—Is It Due for a Repeat of the Powerful 1868 Earthquake?

Top Photo provided By Kimberly Vardeman – Flickr License
Middle Photo provided by NOAA

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