TAG: earthquake monitoring

Researchers See Ionospheric Signature of North Korean Nuclear Test

February 15, 2013By

The explosion of an underground nuclear device by North Korea this week disturbed the Earth’s ionosphere. The blast generated infrasonic waves that propagated all the way to the upper atmosphere causing small variations in the density of electrons there. By analyzing the signals from GPS satellites collected at ground-based monitoring stations in South Korea and Japan, scientists at the California Institute of... read more

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On the Edge: Southwest Shakes

March 1, 2012By
Researchers used data from 25 continuous GPS stations installed as part of the EarthScope Rio Grande Rift GPS experiment, supplemented by data from other GPS monuments in the southwestern U.S., resulting in a data set of daily position estimates of 284 GPS monuments for the years 2006 through 2010.

Using a large network of GPS stations, a team of researchers has found that the Rio Valley Rift in the Southwest United States — previously suspected to be dead — is slowly expanding, at a rate of about 0.1 millimeter per year. The Rio Grande Rift extends from Colorado’s central Rocky Mountains to Mexico. read more

On the Edge: Tracking Slips and Creeps: Earthquake Monitoring Gets Substantial Boost from GPS

July 1, 2011By
Arrow on a Velocity Field Map of Oregon and Washington represent ground motion as measured by GPS at each particular location. The grey circles are 2 sigma error ellipses (click to enlarge.)

The Earth’s surface is constantly shifting, being deformed as earthquake faults accumulate strain, and slip or slowly creep over time. Not long ago, scientists relied solely on seismometers to monitor the earth’s movements. Today, GPS has taken prominence as an indispensible tool. PANGA, the monitoring network covering the Pacific Northwest, uses GPS to monitor this movement by measuring the precise position (within 5 millimeters or less) of stations near active faults relative to each other. By determining how the stations have moved, ground deformation can be determined. read more