Influencing the San Andreas fault line at Parkfield. (Image: David Paul Morris/Getty)
IT’S a kind of geological butterfly effect. Fenglin Niu of Rice University in Houston, Texas, and colleagues believe they have found two clear cases where remote events weakened the San Andreas fault near Parkfield, California. The finding suggests powerful earthquakes – like the one that has just hit Sumatra – may trigger further quakes worldwide.
The first changes to the San Andreas occurred in 1992 after a 7.3-magnitude earthquake several hundred kilometres to the south. The second took place in 2004 after a quake of magnitude 9.1, also in Sumatra,…
