Landers Rupture — Andy on significance of the Landers earthquake
USGS seismologist Andrew Michael talks about the significance of the 1992 Landers earthquake.
A couple days later, I got back to Menlo Park and I would always go and talk to Paul Rosenberg and ask him if anything was new. So this time I asked him if anything was new besides a magnitude 7 earthquake in Southern California and he showed me these amazing plots that showed we had had an increase in seismicity, particularly in volcanic and geothermal regions throughout the western US and literally we had never seen earthquake interactions like that before. And so it was really shocking and amazing to have, you know, to see this really new discovery. Landers has a bunch of lasting legacies; you know the one I've been talking about is the discovery of remote triggering and that became a major research avenue for a lot of scientists. Landers was unique because it was the first really large earthquake we had after we were building dense local seismic networks and so it was our first opportunity to observe this phenomenon. Once we knew it existed we were able to see it after many earthquakes in the future and then start learning how it happened. And you can see the great work done by people like Dave Hill and Joan Gomberg constraining the processes that cause these connections between earthquakes. They probably have an even bigger impact on how we assess earthquake hazards. We clearly saw at Landers that the main shock jumped from one fault to another so that smaller faults that we would usually have treated individually, we're linking up and creating a larger than expected earthquake, and that was a lesson that has really lasted you know until this day in how we interpret small faults out in the field and consider what earthquakes they might produce.