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More about earthquakes, the Richter Scale and volcanic eruptions

| April 26, 2010 9:00 PM

Since late December of 2009, there have been a near-record number of disastrous earthquakes near or above 7.0 on the Richter Scale worldwide, including the deadly tremors in Haiti, Chile and China.

By the end of 2010, it's quite possible that we will set a new yearly record for major earthquakes on a global scale centered mainly in the 'Ring of Fire' Pacific Basin regions.

It's also plausible that at least a couple of 7.0 earthquakes will occur elsewhere along major fault lines in the Middle East, Asia and Africa.

Volcanic eruptions, like this month's travel-restricting blasts from Iceland that stranded thousands of people in Europe and cost the airlines billions of dollars, may likewise increase in the next 6 to 18 months, perhaps enhancing the recent global cooling cycle.

I believe that there is a definite correlation between increasing earthquake activity globally and escalating volcanic events. They seem to go hand-in-hand worldwide.

In the near future, I will write an article featuring greater detail on the earthquake/volcanic eruption connection.

In the meantime, I'm going to answer a subscriber's question concerning just how the Richter Scale works. Its inventor, Dr. Charles F. Richter, was a pioneer in the study of seismology (earthquakes).

The determination of the exact magnitude of a particular earthquake can only be made from precise data gathered from a seismograph located at a specific location on the planet.

By computing this information according to Dr. Richter's formula, it is possible to reach an intensity level ranging between 2 and 9 on the scale, although it's 'open-ended' to some degree.

The specific number is 'logarithmic,' that is, each number is exactly 10 times the quake intensity of the number below it. For example, a 6.0 earthquake is precisely 10 times greater than a 5.0 tremor, etc., etc., etc.

The strongest U.S. earthquake ever recorded happened on Good Friday, March 27, 1964, at Prince William Sound in Alaska. It was measured at an incredible 9.2 on the Richter Scale and devastated the city of Anchorage.

The largest-ever recorded quake in the world happened in Chile. It wasn't the recent shock earlier this year, but the one on May 22, 1965. The epicenter was offshore and measured 9.5 on the Richter Scale.

The most famous quake was the powerful 7.8 magnitude (some estimate an over 8 magnitude) of April 18, 1906, in San Francisco. That disastrous quake killed more than 3,000 people and injured 10,000. Damage totals exceeded a billion dollars, mainly from fires, from Santa Rosa southward to San Jose. That would be more than $50 billion in today's inflated currency.

Following a damaging 6.3 earthquake in the Bay Area exactly a half century later in April of 1956, which "threw people off their feet and houses off their foundations," I wrote my first article of my lengthy career for the school newspaper entitled, "Is There Such A Thing As Earthquake Weather?"

For decades, scientists and others wondered why approximately 65 percent of the most notable earthquakes worldwide 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. It may merely be "coincidental," but all of the earthquakes that I remember while living in California, Vermont and the Inland Northwest occurred either in October in the fall or April in the spring, mostly in April, and usually during, or just after, prolonged dry spells.

Recently, in April of 2001, a 5.1 magnitude earthquake struck interior New England, damaging our home in Jericho, Vt. Sand was pushed by the temblor into our basement, almost collapsing our heating system on the north wall. It was abnormally warm and dry in Vermont that spring, and very windy.

Following an extremely long period of drought in 1988 and 1989, on October 17, 1989, a strong 7.1 quake again struck the San Francisco Bay Area during the World Series just before the start of Game 3 with the Oakland A's at Candlestick Park just south of the city. Dozens of people died when several bridges and overpasses collapsed onto traffic just after the rush hour. Millions across the U.S. and around the world witnessed this disastrous earthquake on television.

Elsewhere across the U.S., some of the biggest earthquakes on record occurred along the New Madrid Fault in the Lower Midwest from December 1811 to February 1812. This region had four tremors above 7.0 on the Richter Scale. The course of the Mississippi River was changed forever.

Last, but certainly not least, let me say that a potentially disastrous earthquake above 7.0 is actually 'overdue' in the Seattle area, but such a large quake is not likely in North Idaho anytime soon. That's another good reason why I chose to live in 'Camelot.'

NEXT WEEK: A thirsty world is running out of water.

NORTH IDAHO WEATHER REVIEW AND LONG-RANGE OUTLOOKS

This past Tuesday afternoon, we got a 'taste of summer' as temperatures soared into the low- to mid-80s across North Idaho.

I logged a warm 83 degrees at my station on Player Drive at 3:20 p.m. It was 85 degrees near Post Falls at the same hour. The 83 degree reading was just a degree cooler than the record for the date of 84 degrees set a couple of weeks before my birth, 68 years ago in 1942. It was the warmest temperature locally since we hit 85 degrees on Sept. 25, 2009, nearly seven months ago. Our upstairs air conditioner was on all evening last Tuesday, perhaps a strong indication of what lies ahead this expected blistering summer of 2010.

In the meantime, we are likely to see some much cooler temperatures and occasional light showers, which we need, during the next week to 10 days before things heat up again in early to mid May. That predicted warm spell will likewise be followed by more showers and cooler temperatures. Such will be the rest of the spring weatherwise, a 'potpourri' of various meteorological fare.

As far as the summer weather patterns are concerned, I still see lots of HOT afternoons near or above the magic 'Sholeh' level of 90 degrees. We may see as many as 25 to 30 such days by the season's end in late September.

Very little rain is expected as high pressure should 'camp out' over the Inland Empire. This could result in some major forest fires into the early autumn period. But, once again, only time will tell ...

SPECIAL BIRTHDAY NOTE

My high school principal, Sterling MacFarlane, turns 94 years young tomorrow, April 27. Happy Birthday, Mac! It will be exactly 50 years in early June since I graduated from high school in Pittsburg, Calif., where Mac was the principal for many years and well-liked to say the least.

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

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