Picture If You Will a Giant Pinball Machine--And you'll begin to get a picture of the extent of shaking caused by the November magnitude 7.9 earthquake in Alaska that affected quite frankly the entire continent, according to the USGS ground-water monitoring network. Yes, that's right, ground-water wells in Pennsylvania, Texas, Connecticut, California and Maine showed strange anomalies of dropping levels and muddy waters almost immediately following the Alaska temblor. The energy released by earthquakes travels not only along the surface causing the damage we're accustomed to seeing on the ground but also travels deep down toward the center of the Earth. Along that voyage energy bounces against deep geologic formations, much like in a giant pinball machine and is bounced or reflected into areas at great distance from the epicenter of the earthquake. That's why ground water in Pennsylvania was showing the effects of the power released by the earthquake more than 3,000 miles away. Talk about your pinball wizardry. Water in lakes and swimming pools sloshed about thousands of miles from the epicenter while similar sloshing occurred in aquifers leading to water-level changes and muddy wells. Butch Kinerney (bkinerney@usgs.gov) 703-648-4460

Red is High; Blue is Low Where Do You Live?--Curious as to whether or not you live on shaky ground? There are more than 75 million Americans in 39 states who live in cities with moderate to high risk from earthquakes. USGS scientists and their partner colleagues have just revised and updated the national seismic hazard maps that provide information essential to seismic design provisions of building codes in the United States. This means that engineers and planners now have updated information to ensure that buildings, bridges, highways and utilities are built or rebuilt to meet modern seismic design provisions and that means they're better able
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Contact: Office of Communications
hfriesen@usgs.gov
703-648-4460
United States Geological Survey
9-Dec-2002