Recent Experiences Operating a Large, International Network of Electromagnetic Earthquake Monitors

Wednesday, 17 December 2014
Tom Bleier1, John Clark Dunson2 and James Lemon2, (1)QuakeFinder, Portola Valley, CA, United States, (2)QuakeFinder, Palo Alto, CA, United States
Leading a 5-nation international collaboration, QuakeFinder currently has a network of 168 instruments along with a Data Center that processes the 10 GB of data each day, 7 days a week. Each instrument includes 3-axis induction magnetometers, positive and negative ion sensors, and a geophone.

These ground instruments are augmented with GOES weather satellite infrared monitoring of California (and in the future—other countries).

The nature of the signals we are trying to detect and identify to enable forecasts for significant earthquakes (>M5) involves refining algorithms that both identify quake-related signals at some distance and remove a myriad of natural and anthropogenic noise.

Maximum detection range was further investigated this year. An initial estimated maximum detection distance of 10 miles (16 km) was challenged with the onset of a M8.2 quake near Iquique, Chile on April 1, 2014. We will discuss the different strategies used to push the limits of detection for this quake which was 93 miles (149 km) from the instrument that had just been installed 2 months before the quake.

Identifying and masking natural and man-made noise to reduce the number of misses and false alarms, and to increase the number of “hits” in a limited earthquake data set continues to be a top priority. Several novel approaches were tried, and the resulting progress will be discussed.