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Recent Earthquake magnitude 6.2 in Tacna, Peru.
Analysis
Collaboration between QuakeFinder and the Catholic University in Lima Peru (PUCP)
Both California and Peru have a large risk due to earthquakes. Peru had a M8 earthquake on August 15, 2007 and California has had a number of large quakes in the past (Loma Prieta, Northridge, Landers, etc.). QuakeFinder entered into a collaboration with Dr. Jorge Heraud at PUCP in 2009 to install 2 ultra low frequency magnetometer systems in Peru, at locations where there was a higher than normal probability of large earthquakes in the near future. The sites chosen were at El Carmen near Chincha (near the M8 quake), and at Los Palos, near Tacna Peru and the Chilean border to the south. This collaboration was rewarded on May 5th, 2010 when a M6.2 quake occurred approximately 29km from the Los Palos, Tacna site. Quakefinder Stations |
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Peru Map |
Magnetic Pulses:
Positive or negative only magnetic pulsations about 0.3 to 10 sec. long appear to be the "signal" that is associated with recent earthquakes, and they started to appear on April 23, 12-13 days prior to the M6.2 quake. The upper (green) and lower (red) horizontal lines are threshold limits, and only the pulses which exceed these are counted.
Magnetic Pulse Count:
Noise from a recent solar storm, e.g. bi-directional oscillations, were removed from the data and the threshold limits were tightened to identify the pulses. The remaining unipolar pulses, similar to the Alum Rock quake, were counted and observed to increase from under 20 per day to over 120-160 per day within the 2 weeks prior to the quake, and then disappear after the quake.
Air Conductivity:
Air conductivity, or the presence of charged carriers in the air a few meters above the ground, also showed that negative charged particles increased over 300% within a week prior to the quake, and then disappeared after the quake. Both magnetic pulses and air conductivity support a recent NASA (Freund) theory about how the changing stress at the hypocenter causes large underground electrical currents and magnetic field pulses.
for more details on the ULF theory.
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