PREDICTION Paleoseismology: Documenting and evaluating past events. 1.) Usually done with looking at offset layers in sediments in trenches 2.) Calculate recurrence interval by using radiometric dating Carbon14. ND pg. 111 Fig. 4.21/4.22

PREDICTION E-W patterns: Consider Bay area earth quakes. *A given EQ is usually followed by another in the near future to the east or west. Fig. 4.27

PREDICTION Seismic Gap: Areas of fault that seem to be stuck for periods of time. *Recall Elastic Rebound Theory *Consider areas of specific fault-(Fig. 4.14) *Consider general geographic area-(ND pg. 118/fig. 4.32)

PREDICTION and WARNING Some other interesting techniques that we can use… *US and JAPAN utilize this technology 1.) Stainmeters measure the amount of “bend” in rocks 2.) Tilt measurements - is the tilt of the surrounding rock changing? 3.) Radon-crystals fracture and release radon gas Earth and Environmental fig

While these all provide insight there is NO OBVIOUS/FORMULAIC pattern to perfect prediction/warning 4.) Groundwater-level and temperature fluctuations 5.) Electrical conductivity - as rocks compress they lose resistance (conductivity increases) 6.) Leveling surveys and lasers - are different sides of the fault changing up,down,side to side Earth and Environmental fig PREDICTION and WARNING continued

PREDICTION Intermediate- Long-Term Predictions: Can we do it? Faults can be characterized into 3 main groups: 1.) Quasi-Periodic: Major events or events of certain magnitude happen at nearly regular intervals 2.) Clustered Movements: movements occur for periods of time (decades) the quiet for periods of time (centuries) 3.) Random- Well just that. We got nothin’. San Andreas?

PREDICTION BUT!!!!!!! Haicheng China, Winter of 1975 Precursors: 1.) land elevation changed (laser and satellite data collection) 2.) water level changed unexpectedly (ground and surface) 3.) minor foreshocks increased in frequency Action: 1.) An evacuation was ordered 2.) On Feb. 4 a 7.3 hit. 3.) killed 2,041 injured 27,538 4.) potential fatalities could have been 150,000

PREDICTION BUT BUT!!!!! Tangshen China 1.) July 28, ) 7.3 EQ 3.) similar tectonic setting NO precursors recorded 4.) 250,000 people perished.