Earthquake and volcanic activity may be increasing globally

It seems that the focus this last week was not so much on the weather, but the recent earthquake activity. On Saturday, April 25, a massive 7.8 earthquake hit Nepal, a mountainous nation between India and Tibet which is known for its hiking, wildlife and temples. The big quake killed over 6,000 people and also triggered an avalanche on the slopes of Mount Everest. There have been numerous aftershocks, including a strong 6.7 on Sunday, April 26.

Rare earthquakes were also felt in North Idaho last week. Many earthquakes continue to be felt in central Oklahoma. Since 2008, they've occurred 600 times more often than usual. Some scientists are blaming the oil and natural gas drilling operations as the possible cause of the increased activity.

Some of the largest earthquakes in the U.S. have been recorded in the Midwest. In 1811-12, the New Madrid earthquakes in southeastern Missouri produced shakers from about 7.2 to 8.6. The first known earthquake in that region was on Dec. 25, 1699, as French missionaries reported ground tremors. More recently, the biggest earthquake was a 5.4 magnitude on Nov. 9, 1968, near Dale, Ill. Since 1974, there have been over 4,000 quakes recorded, but most were too small to be felt. Scientists believe that another major earthquake is due for this region within the next 100 years.

Since the late 1970s, earthquakes have been measured by the Moment Magnitude Scale (MMS), which replaced the Richter Scale. The MMS is used by seismologists to more accurately measure the size of earthquakes, especially the larger ones.

Of course, most of the large earthquakes occur along major fault boundaries. California is the most famous with the San Andreas Fault. Small earthquakes occur on a daily basis in the Golden State, but many are not felt as they are too weak and too deep within the ground.

The largest U.S. earthquake was on Good Friday, March 27 in 1964. This was "The Great Alaskan Earthquake" near Anchorage and it measured a whopping 9.2, the second largest recorded quake globally in recorded history. The shaking lasted for 4 minutes and 38 seconds and caused $311 million in damages. This major quake event produced two tsunamis as waves were seen as far south as New Zealand in the Southern Hemisphere.

There have also been large earthquakes in Washington and Idaho. On Oct. 28, 1983, there was a 6.9 event in the Lost River Range at Borah Peak in central Idaho. Total damage was about $12.5 million. One of the largest earthquakes in recent times in Washington happened near Lake Chelan on Dec. 14, 1872. It measured 6.8 and was felt from British Columbia to Montana. On Feb. 28, 2001, the Nisqually earthquake was also recorded at 6.8 and was centered on Anderson Island, about 11 miles northeast of Olympia, Washington. There was some property damage in Seattle and the surrounding areas.

Believe it or not, an even bigger earthquake is possible in the Pacific Northwest within the next 100 years. The last big one hit the Pacific Northwest coastline back on Jan. 26, 1700. The magnitude was estimated between 8.7 and 9.2 and triggered a tsunami that hit the coast of Japan, killing thousands of people.

The average number of earthquakes across the globe is about 500,000 each year. Most occur along the "Ring of Fire" in the Pacific Ocean, where we also see most of the huge volcanic eruptions like we saw this past week when the violent Calbuco Volcano erupted in southern Chile. Most of the inhabitants of Ensenada had to be evacuated. Another major eruption of Calbuco occurred on Thursday, April 30. More eruptions are said to be "imminent."

NORTH IDAHO WEATHER REVIEW AND LONG-RANGE OUTLOOKS

With the rebirth of El Nino in the waters of the east-central Pacific Ocean, our weather turned dry and rather warm again after the early April snows. The average afternoon maximum reading during the second half of April was a pleasant 67 degrees compared with just 54 degrees during the first half of April. Our average (mean) high for the month was 60 degrees compared with the normal since 1895 of 57 degrees. Our average low temperature was 35 degrees this April, one degree above the 120-year normal of 34 degrees.

As far as precipitation was concerned, our total April rainfall was 1.24 inches, well below the normal total since 1895 of 1.77 inches. The last 16 days of April had a combined precipitation total of a puny .19 inches, less than 20 percent of normal. I'm glad that I turned our sprinklers on this spring a full month ahead of schedule.

Looking farther down the meteorological highway, I see increasing shower activity in the Inland Northwest along with scattered thunderstorms late this week into the middle of May. But, once again, thanks to the rejuvenated El Nino event in the Pacific Ocean waters, precipitation amounts may remain less than normal overall between now and at least the end of September or early October.

In other words, folks, it still looks like we'll see a long, dry and rather hot late spring, summer and early fall six-month period across North Idaho.

Cliff Harris is a climatologist who writes a weekly column for The Press. His opinions are his own. Email sfharris@roadrunner.com