In midst of pandemic, earthquakes strike

While everyone is doing their best to get through this coronavirus pandemic, some places have been forced to deal with earthquakes and aftershocks last week.

On Wednesday, March 18, a 5.7 magnitude earthquake shook the Salt Lake City area. Fortunately, there were no reports of injuries or major damage to buildings. However, there was extensive damage to mobile homes near the quake’s epicenter.

Since the first earthquake hit the area, there have been over 160 aftershocks. This was the largest earthquake to strike Utah since 1992, when a 5.9 magnitude quake was reported in southern part of the state.

On March 18, a 5.2 magnitude earthquake rattled residents along the northern California coastline. The epicenter was located about 35 miles to the southwest of Eureka and nearly 10 miles off the coast. That particular earthquake was also close to the region of another one that occurred on March 8 with a magnitude of 5.8.

On Friday, March 20, a 4.5 magnitude earthquake struck near the Lake Tahoe area in Nevada. The epicenter was very close to Carson City, Nevada’s state capital. California and Nevada will average approximately five earthquakes a year with magnitudes between 5.0 and 6.0.

The western U.S. was not the only part of the country to experience earthquake activity last week. On March 16, there were five quakes, smaller in magnitude, that hit the Carolinas and Tennessee within a period of 24 hours. The highest was a 2.4 magnitude near Centerville, S.C., according to the U.S. Geological Survey.

Across the world, there was a 5.9 earthquake in Tibet on Friday. There was a strong earthquake measuring 6.2 in Bali, Indonesia on March 19.

From March 14 to March 20, there were 2,758 earthquakes in the U.S., with 83 of them registering at or higher than 2.5 in magnitude. Across the world, there have been 422 earthquakes that were 2.5 or higher in a week’s time.

Despite the recent activity, according to the USGS, there are an average of 1,319 earthquakes worldwide measuring between 5.0 to 5.9 each year. There were 324 as of late last week, which is a little above the average to date. The 6.0 to 6.9 range has about 134 per year. The USGS has reported 23 across the globe since Jan. 1.

There are approximately 15 massive 7.0 to 7.9 earthquakes each year across the globe. Through March 20, there have been only two, including the 7.7 quake in Jamaica on Jan. 28. So far, there hasn’t been an earthquake with a magnitude of an 8 or higher in 2020. The average for an earthquake of that size is one per year.

Althoug major earthquakes here in the Pacific Northwest are not very common, scientists are concerned about a potential large event along the coast of Washington. Based on historical evidence, there was a huge megathrust earthquake on Jan. 26, 1700 that was known as the Cascadia earthquake. It happened across a 620-mile area along the Cascadia subduction zone from the middle of Vancouver Island in British Columbia, Canada southward along the Pacific Northwest coast down into northern California. The magnitude was estimated between 8.7 and 9.2. The devastating Alaskan earthquake in 1964, the second largest recorded in history, was a 9.2.

Prior to the event in 1700, based on estimated geologic evidence, there may been seven major earthquakes in the last 3,500 years, perhaps about 500 years apart. Research from cores obtained from the seafloor indicate that there have been 41 major earthquakes in the region over the past 10,000 years. Some experts say there is a 33 percent chance that the Pacific Northwest could see a major earthquake within the next 50 years.

Experts also believe that California will be rocked by a massive earthquake by 2037. They believe there is a 99.7 percent chance the Golden State will be hit with a magnitude of 6.7 or higher within the next 30 years.

In terms of our local weather, it was fairly mild during the last gasp of winter. Last Friday, Cliff measured a high of 60 degrees at his station in Coeur d’Alene. Most other locations in the region reported high temperatures in the upper 50s and lower 60s.

Despite the recent springlike weather, temperatures will be getting cooler. By late in the week, a storm system is expected to bring rain and perhaps some snowfall in the lower elevations during the nighttime hours.

The long-range computer models are indicating that another chilly system from the north will bring our region a chance of more snow around April 1 (no foolin’). There’s also another chance that we’ll have some snow around the full moon cycle of April 7.

After the middle of next month, Cliff and I believe that our snowfall season will come to an end, with totals near or a little below the seasonal normal of 69.8 inches.

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Contact Randy Mann at randy@longrangeweather.com