Shakers Are Piling Up
An automobile lies crushed under the third story of this apartment building in the Marina District of San Francisco. The ground levels are no longer visible because of structural failure and sinking due to liquefaction, October 17, 1989, Loma Prieta, California [J.K. Nakata, USGS]


In the U.S., earthquakes pose significant risk to 75 million
Americans in 39 states. —USGS Jan. 2004
June 22, 2010
By Holly Deyo

Below is a chart I've maintained for nearly two decades showing how we fair each year with earthquakes. During the first 6 months of 2010, averages are already filling up. The largest shaker quota has already been filled. Richter 7 averages are more than 50%. Magnitude 6's and 5's are well over expectations. It's likely that this is attributable to many aftershocks from larger quakes.

Periodically quake data are "adjusted" by USGS. For example, in rechecking statistics for 2007, USGS had previously noted 5 mag. 8.0-9.9 events. Now it shows 4. When this occurs, normally the next lower Richter picks up the slack. Not this time. USGS data used to show 16 Richters 7s. That, too, was decreased by 2 events to 14. Where did these quakes go? It's pretty hard to "disappear" events of this size.

Looking at the major U.S. quakes of the past 100 years, we can expect a good shake every decade. Sooner or later the U.S. can expect a mighty thump and it looks like we're due... Of the 16 events below, 11 occurred during the first 6 months of the year.

April 4, 2010 (Easter Sunday)7.2 struck about 19 miles southeast of Mexicali, a bustling commerce center of more than 900,000 people on the Mexican side of the border where trucks carry goods cross into California. Technically the epicenter was just across the border, but it damaged U.S. property and was widely felt throughout the western states, some southern zones, and northwest Mexico. The earthquake was the strongest to rock Calif. in at least 18 years lasting about a minute and a half. It left 4 dead and 100 injured in Mexico.

Nov. 3, 2002 7.9 quake centred on a sparsely populated area south of Fairbanks, Alaska was felt from the Arctic Circle to the Gulf of Mexico. It appears to have caused remarkably little serious damage and only minor injuries.

Feb. 28, 2001 – 6.8 quake southwest of Seattle damages the Washington state capitol, briefly closes Seattle-Tacoma International Airport.

Oct. 16, 1999 – 7.0 quake in California's Mojave Desert derails an Amtrak train, knocks out power to thousands but causes no serious damage or injuries.

Jan. 17, 1994 – 6.7 quake in Northridge, California, in the San Fernando Valley in northern Los Angeles killed 60 people, injured more than 7,000, left 20,000 homeless and damaged more than 40,000 buildings. It collapsed overpasses, closing sections of four major area freeways. Damage estimates ranged from $13 billion and $30 billion.

June 28, 1992 – 7.3 quake in Landers, California near Yucca Valley in the Mojave Desert killed one person and injured 400. It was felt throughout the Southwest.

Oct. 17, 1989 – 6.9 quake in the Santa Cruz Mountains near the Loma Prieta Mountains in northern California killed 63 people, caused 3,757 injuries and an estimated $6 billion in property damage. The most severe damage occurred in Oakland and San Francisco about 60 miles north, where several sections of major freeways collapsed.

Feb. 9, 1971 – 6.6 quake struck in a sparsely populated area of the San Gabriel Mountains in Southern California. It killed 65 people, injured more than 2,000 and caused property damage estimated at more than $505 million.

March 28, 1964 – Alaska - 9.2 earthquake and ensuing tsunami claimed 128 lives and caused about $311 million in property losses.

Aug. 18, 1959 – The largest earthquake to hit Montana in recorded history, it measured 7.3, caused 28 fatalities and caused about $11 million in damage to highways and timber.

March 9, 1957 – 9.1 quake hit the Andreanof Islands of Alaska. On Umnak Island, Mount Vsevidof erupted after being dormant for 200 years, generating a 50-foot(15-metre)-high tsunami that continued to Hawaii.

July 21, 1952 – 7.3 temblor killed 12 people and caused $60 million in damage, much of it around Bakersfield, California.

April 13, 1949 – 7.1 quake near Olympia, Wash., kills 8.

April 1, 1946 – 8.1 quake struck Unimak Island in Alaska, where it caused only minor damage to buildings, but generated a 115-foot(35-metre)-high tsunami that destroyed the island's lighthouse and swept away its five occupants. The tsunami killed 159 people in Hilo, Hawaii where it caused $26 million in damage, and killed one person in California. (source: AP & reuters)

March 10, 1933 – 6.3 quake in Long Beach, Calif., kills 115 people.

April 18-19, 1906 – 7.8 (estimated) quake and fires level San Francisco, killing an estimated 700 people.



GLOBAL EARTHQUAKES JANUARY 1, 1992 - JUNE 22, 2010

Mag. 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001
2002
 2003 2004 2005 2006 2007 2008 2009 2010 USGS
Quake
Ave.
for a
Year
Thru
June 22,
2010
8.0 - 9.9
Great
 0 1 2 3 1 0 2 0 4 3
1
 1 2 1 1 4 0 1 1 1
100%
7.0 - 7.9
Major
 24 15 13 22 21 20 14 23 16 15
12
 16 14 11 11 14 12 16 9 17
53%
6.0 - 6.9
Strong
 163 141 161 185 160 125 113 123 153 124
130
 145 146 154 139 178 168 142 86 134
64%
5.0 - 5.9
Moderate
 1,521 1,449 1,542 1,327 1,223 1,118 979 1,106 1,345 1,243
1,218
 1,252 1,637 1,954 1,529 2,072 1,768 1,700 941 1319
71%
4.0 - 4.9
Light
 5,153 5,034 4,544 8,140 8,794 7,938 7,303 7,042 8,084 8,084
8,584
 8,454 10,783 13,702 13,048 12,105 12,292 6,980 4,411 13,000
34%
Deaths 3,814 10,036 1,038 7,949 419 2,907 9,430 22,711 231 35,000-
40,000*
1,712
 43,819 284,010 82,364 6,605 712 88,208 1,787 225,492 10,000
2255%


*NOTES: At the end of September 2003, the USGS adjusted earthquake global averages for magnitudes 4, 5, 6 and 7. Most have increased, one magnitude decreased in shaker averages. This indicates an overall increase in earthquake activity. To get a fair comparison, both the "old" and "new" averages are included in the chart above.

The exact number of deaths from the January 26, 2001 India earthquake will never be known. According to the Red Cross, "Death toll reports vary widely, with some ranging from more 20,000 to as many as 100,000."