Landers Rupture — Jonathan Fieldwork

I’m a general geologist, I'm not a fault specialist or an earthquake specialist. I think when an event like that goes off, it's all hands rallying around the flag to represent the US Geological Survey’s interest and specialty and expertise in this kind of thing. So when I arrived out there shortly after the earthquake we had a team meeting in a motel room there and we were told what was to be expected of us. It was truly a team effort where they sent individuals along particular segments of the earthquake rupture so I was quote unquote assigned where to go and what to look for. And then I received a little bit of training from some of the experts on how to interpret fractures that one can see on the earth surface, the kinds of things to look for in terms of measuring offsets carefully, and you just don't throw a yard stick on the ground and measure something pretty easily, you gotta sort of visualize what had been offset. As you know, it was a strike slip earthquake, a right lateral strike slip earthquake, with the associated ground rupture and so a feature on one side of the fault has been displaced to the right relative to a feature on the other side so you gotta identify an obvious and documentable feature and then make certain that you're measuring the offset  geometrically in the correct fashion and there are certain rules of thumb you have to use to do that.