December 4, 2012
Russian Far East A Hotbed Of Seismic, Volcanic Activity: Potential Threat To Pacific Basin
April Flowers for redOrbit.com - Your Universe Online
The Soviet government has long kept outsiders away from the Russian Far East, shrouding a source of powerful earthquakes and volcanic activity on the Pacific Rim in secrecy.
In the last 20 years, however, research has shown that the Kamchatka Peninsula and the Kuril Islands are a seismic and volcanic hotbed. This area has the potential to trigger tsunamis that pose a risk to the rest of the Pacific Basin. As an example, in 1952, a magnitude 9 earthquake in the region caused significant damage elsewhere on the Pacific Rim. Even less powerful quakes have had damaging effects throughout the Pacific Basin.
“There´s not a large population in the Russian Far East, but it´s obviously important to the people who live there. Thousands of people were killed in tsunamis because of the earthquake in 1952. And tsunamis don´t stay home,” said Jody Bourgeois, a University of Washington professor of Earth and space sciences.
Bourgeois presented her findings on the seismic and volcanic threats in the Kamchatka-Kuril region at the fall meeting of the American Geophysical Union on December 3.
In 2006 and 2007, earthquakes registering over magnitude 8 struck the central Kurils, producing large local tsunamis up to about 50 feet. While tsunamis that crossed the Pacific were much smaller, the one associated with the 2006 quake did more than $10 million in damage at Crescent City, California.
Air traffic over the North Pacific was disrupted in 2009 when Sarychev Peak in the Kurils erupted spectacularly.
Bourgeois said that determining the frequency of such events is of great importance to many people.
“Let´s say you decide to build a nuclear power plant in Crescent City. You have to consider local events, but you also have to consider non-local events, worst-case scenarios, which includes tsunamis coming across the Pacific,” she said in a statement.
This depth of understanding is possible only when the nature of the hazards is understood. The historic record for earthquakes, tsunamis and volcanoes is relatively short for the Kamchatka-Kuril region, and because it was closed to outsiders for decades, much of the information is only now becoming available on the Internet.
Bourgeois says that much has been learned in the last ten years in the examination of tsunami deposits and other evidence of prehistoric events. More field work is necessary, however, in the Kamchatcka-Kuril subduction zone to gain a clearer picture.
“For hazard analysis, you should just assume that a subduction zone can produce a magnitude 9 earthquake,” she said. So it is important to “pay attention to the prehistoric record” to know where, and how often, such major events occur.
In the last 25 years, research into the Cascadia subduction zone off the coast of Washington, Northern California and British Columbia has revealed that the historic record does not provide a good characterization of the potential hazard. Scientists long assumed that the risks in the Northwest were small, but further research has shown that at least once, before written records, Cascadia produced a magnitude 9 earthquake and a tsunami that hit Japan.
The Aleutian Islands and the Komandorsky Islands — a Russian controlled extension of the Aleutians - are another source of seismic and volcanic activity that need to be evaluated for potential risks beyond those known in the historic record.
“The Aleutians are under-studied,” Bourgeois said. “The work in the Russian Far East is kind of a template for the Aleutians.”
A dedicated boat could ferry researchers from the mainland to a number of islands in the Aleutian chain. This is similar to how Bourgeois and other scientists carried out research in the Kuril islands.
“The problem is that during the (research) field season, boats are commonly in demand for fishing,” she said.