Far Field Aftershocks. Denali Quake
Posted by Don in Hollister on October 28, 2003 at 02:13:33:

Hi All. Did the Denali quake trigger these quakes, or was this just a coincident? These quakes could be nothing more then a coincident, but the quake in Utah would appear to rule that out. The question always come to mind when something likes this occurs. Would these quakes have occurred anyway, but only a few days earlier then they were going to? Of course there is no answer for this question as there is no to know if those quakes were going to occur 11/06/2002, but the Denali quake moved the clock forward 3 days.

Earthquakes happen everyday-but not like this. One of the largest earthquakes recorded in American history occurred on the quiet Sunday afternoon of November 3, 2002 in a sparsely populated area about 80 miles south of Fairbanks, Alaska. Known as the Denali quake, the event measured 7.9 (depending on scale used) in magnitude (a size, scientists say, that could level a city like Los Angeles) and was felt as far away as Louisiana.

“Stephanie Prejean, a scientist with the United States Geological Survey (USGS) in Menlo Park, California, presented data during a special session at the meeting on earthquakes that occurred in Washington and California 15 to 17 minutes after the Denali quake.”

“At Mount Rainier in central Washington, a series of small earthquakes measuring less than magnitude 2 occurred over a few minutes. At Geysers Geothermal Field in western California and Coso Geothermal Field in southeastern California, small quakes lasted for roughly 30 minutes.”

“In Utah the number of small earthquakes increased significantly following the Denali event, according to Kristine Pankow of the University of Utah. This increase in seismicity included a magnitude 2.6 quake that occurred at the same time the rolling energy from the Denali quake hit Utah, leading scientists to speculate that the Alaska earthquake triggered the events.”

“Nearby in Yellowstone National Park in Wyoming, more than 200 small earthquakes were recorded in the 17 hours following the Denali quake, the largest measuring magnitude 2.5. Small earthquakes in Yellowstone are not uncommon in focused locations, but this series of events was unusual because it spread throughout the park and was not restricted to one spot.”

When one looks at the location of the quakes it could be said that the quakes occurred in the area of weak faults. That would appear to be the case in regards to the quakes at Mount Rainier, Geysers Geothermal Field, Coso Geothermal Field and Yellowstone, or could it be that because they are associated with areas that are volcanic that there was an increase in quakes?

Lots of questions, but not many answers. Take Care…Don in creepy town