Research Parkfield_earthquake

predicting 2004 event 1993

geologists hoped study happens before quake, , in particular signs might enable them predict future earthquakes, installed elaborate array of seismometers, creepmeters, strainmeters, , other instruments in , around parkfield starting in 1985. scientists usgs , uc berkeley had predicted, 90 95% confidence level, earthquake strike parkfield area between 1985 , 1993. known parkfield earthquake prediction , parkfield earthquake experiment, conducted usgs. attempts @ predicting quake continued until january 2001, earthquake of 5.5 magnitude or greater did not occur 1985 until 2004 quake.

in june 2004, usgs in partnership national science foundation began drilling deep hole house instruments monitor fault @ depth. action part of san andreas fault observatory @ depth (safod) program.

because of regularity of large events (mb>5.5) @ parkfield location (events in 1857, 1881, 1901, 1922, 1934, , 1966), , fact waveforms many of these events identical, believed same segment of fault ruptured each time. led prediction in 1984 of similar event in 1993.