Quakefinder Blog

108 year anniversary of the 1906 San Francisco Earthquake

At 5:12 AM on April 18, 1906, the ground shook like it had never done before in San Francisco. An estimated Magnitude 7.8 earthquake broke the city, and started numerous fires that decimated what was left of many structures. Over 3,000 people died. This major earthquake ruptured 296 miles (477 kilometers) of the San Andreas Fault from San Juan Bautista to Cape Mendocino. No warning was available then. Even today, 108 years later, there is no accepted warning system for such a quake. In 1906, horses were reported to be agitated in the barns near the Presidio prior to the quake. What were they sensing? We think that they may have sensed ultra low frequency magnetic waves or static electricity from ionized air around them. Today we have instrumented much of the San Andreas and other major faults in California with sensitive magnetometers and air ionization sensors to see if these phenomena occur regularly before large quakes. We are actively collecting a valuable “baseline” of electromagnetic signatures for these faults. The hope is that future major quakes repeat the same two week sequence of magnetic pulses and air conductivity changes observed by QuakeFinder instruments that preceded the M5.4 Alum Rock, CA and M6.2 Tacna, Peru quakes in 2007 and 2010 respectively.

April 1, M8.2 quake and several M7’s near Iquique, Chile

The massive M8.2 quake near Iquique, Chile on April 1 reminds us that the northern area of Chile near the Peru border had been long overdue for a large earthquake. QuakeFinder has been concerned about this area since 2010 when we installed 4 sites on the Peru side of the border. In January 2014 we installed a new site 40 miles (approximately 64 kilometers) south of Iquique, working with our partners at Pontificia Universidad Catolica de Chile in Santiago, Universidad de Concepción, Universidad Andrés Bello (UNAB), and Center of the Desert in Iquique. The earthquake happened to the NW of Iquique about 90 miles (144 kilometers) from that site. Our range of detection is around 10 miles (16 kilometers), but the M7.8 was 27 miles (44 km) from our site and may show that the aftershocks are migrating closer to our lone site there. Our small network in Chile needs to be expanded to cover more critical areas, and we are continuing to look for partners to assist in this effort.  With this site near Iquique, we are excited to be in the right area and continuing analysis of these quakes will advance the state of the art of earthquake forecasting. Get involved. Contact us at supportQF@quakefinder.com