English: Magnitude_7.0_BANDA_SEA (Photo credit: Wikipedia)

This article is fascinating — apparently scientists have discovered that an earthquake greater than an 8.0 on the Richter Scale may cause errors with GPS systems. Apparently the shift in the earth may throw off GPS measurements.
Article:
http://www.dnaindia.com/scitech/1841127/report-earthquakes-greater-than-8-0-magnitude-create-gps-errors