Could 10.0 quake be brewing?

Over the last 30 days, there have been nearly 500 earthquakes with a magnitude of 4.5 or higher in the world. However, in the Continental U.S., there was only one earthquake of 4.5 or higher since the middle of March. It was a 4.5 magnitude in New Mexico on March 16.

Across the globe, the highest within the last month occurred on March 20 near Ishinomaki, Japan with a relatively strong 7.0 magnitude.

According to the United States Geological Survey, it's normal to see temporary increases or a decrease in seismic activity. Scientists say the fluctuation does not indicate that a major quake is around the corner.

With our current technology, predicting a major earthquake is not possible. Scientists can only come up with probabilities of earthquakes occurring in specific areas over a period of years.

Right now, most predictions rely on estimates based upon the analysis and calculations of vibrations in the Earth’s crust. However, scientists in China are developing a new automated system that has already shown better accuracy. By using artificial intelligence and constant monitoring, the system may provide better long-term predictions and help other earthquake-prone countries like Japan that lie along the “Ring of Fire.”

There was one historical instance where a major earthquake was predicted. In 1975, the Haicheng earthquake hit China on Feb. 4 with a magnitude of 7.5. Officials made the prediction of the upcoming quake based on smaller earthquakes and unusual animal activity.

There was an evacuation of most of Haicheng’s population prior to the big quake and the efforts saved many lives. Unfortunately, the next big earthquake in China had no indicators and resulted in thousands of deaths.

Many people believe that unusual animal behavior is a sign of an upcoming earthquake. According to the USGS, many species of animals including rats, snakes and weasels left their homes days before a massive earthquake in Greece in 373 B.C.

More recently, people have described unusual animal behavior prior to an earthquake such as continuous dog barking and cows stopping their milk. A recent article from ScientificAmerican.com shows that numerous studies are finding scientific links between unusual animal behavior and earthquakes.

The largest-ever recorded quake happened in Chile on May 22, 1965. The epicenter was offshore and measured 9.5.

Chile had another big quake that measured 8.8 on Feb. 27, 2010.

The strongest U.S. earthquake ever recorded happened on Good Friday, March 28, 1964 at Prince William Sound in Alaska. It had an incredible magnitude of 9.2, which devastated the city of Anchorage and also generated a massive tsunami. The quake was so strong that it was felt as far away as Florida.

In 1700, a very strong earthquake estimated at 8.7 to 9.2 hit the northwestern portions of the country from British Columbia down into California. The quake likely generated a tsunami that hit the coast of Japan.

Many people have wondered if we could see a 10.0 magnitude earthquake anywhere in the world. Scientists say that size of an event is not possible because the earthquakes are related to the length of faults, or cracks in the Earth. The big quake in China in 1960 had a fault of 1,000 miles long and there is no known fault long enough to trigger such an event.

In our region, the largest quake occurred in 1942 and was centered 35 miles northeast of Spokane. It measured a 5.5 on the Richter Scale.

In 2001, Spokane was in the throes of an "earthquake swarm." Nearly 100 earthquakes were recorded over a six-month period with a 3.7 magnitude reported on June 25, 2001. Scientists are still uncertain why our region experienced this swarm of quakes.

Others have wondered if there is a connection between the weather and earthquakes. Geologists maintain that there is no relationship as seismic activity is the result of geologic processes within the earth and can happen in any weather and any time during the year.

However, some scientists and others wondered why approximately 65 percent of the most notable earthquakes nationwide were occurring in the spring and fall seasons and only about 35 percent in the winter and summer periods. In other words, are there "earthquake seasons," much like hurricane, snow and tornado seasons? Maybe yes, maybe no.

In terms of our local weather, we finally got some much-needed rainfall over the weekend. Despite the recent moisture, April’s precipitation total in Coeur d’Alene is expected to end up below the normal of 1.77 inches. We still see a wetter-than-normal period developing later next month, but the upcoming summer season still looks drier and warmer than average.

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Contact Randy Mann at randy@longrangeweather.com