Eighty Years, Twenty Years, Three Years discussed on Morning Edition


To harness the power of research to make a difference in the lives of children teens and young adults for more than eighty years learn more at W. T. grant FDN dot org it's morning edition from NPR news I'm Steve Inskeep and I'm Rachel Martin California can't quite breathe a sigh of relief two of the biggest earthquakes rattle the state in decades did not result in any major injuries but scientists say it's a sign of what's to come your sub governor Gavin Newsom but we all have an opportunity now to get more prepared to be more vigilant to look at our building codes look at home hardening Ross Dunn is a scientist emeritus at the US Geological Survey and creator of the seismic risk tool called to him lord dot net he joins us now thanks so much for being with us happy to do so first off just how unusual is it to have back to back earthquakes like this the second even stronger than the first well it happens it's not the typical deal normally we have a bigger earthquake and it's followed by smaller ones to get space farther and farther apart but three years ago in Japan we had a magnitude six in Kumamoto on the south island of Japan and a day later we had a magnitude seven at the same spot expanding much like this earthquake that occurred in the last few days why didn't a seven point one earthquake cause more damage well first of all let's just take the good news where we can get it that's wonderful but second it's all about location this is one of the most sparsely populated though beautiful parts of California the high desert area so there were no tall buildings and they're very very few homes compared to if we put the same earthquake for example in the San Francisco Bay Area on the Hayward fault who would have a hundred times a thousand times more buildings exposed to the shaking and we would have much softer sentiments that amplify the shaking her how how much better prepared is the state of California for a devastating earthquake than it was twenty years ago well that's kind of a trick question on the good news side PGA any has done an enormous job in bolstering and hardening their system of pipelines and conduits cal trans the E. S. state transportation department is done the same and there are more ordinances that require or encourage people to retrofit multi unit buildings but on the flip side only a small percentage of the population Kerry's insurance and a very small percentage of older homes have been seismically retrofit to make them stronger so it's definitely a good news bad news situation and maybe this is another reminder that we can turn this into all good news if we get prepared do earthquakes like this does this increase the risk in other parts of the state I mean should people long other fault lines be concerned right now probably not never the less this earthquake has stressed its neighboring fault and we're beginning to see earthquakes on those faults so just to the south of this rupture is the Garlock fault that's almost two hundred miles long and it connects to the San Andreas in the last day we've seen about a dozen earthquakes on it not far from where this one occurred so it's always possible that this earthquake will trigger another event on in neighboring fault and that could propagate into more populated areas what did you learn from this well earthquakes or any kind of conversation or not isolated advance we talk about the big one we should instead talk about the big ones this the most surprising thing about this earthquake is it occurred on a fault very straight simple fault that we didn't know about and that we would have thought that for California any fault capable of a magnitude seven would have been mapped and known and so it's a humbling moment when we realize that the there's a lot of surprises out there for us even in California Rothstein of the U. S. Geological Survey and founder of ten lord dot net thanks so much for time you bet this is NPR news support comes from LA county department of beaches and harbors presenting the marina del Rey summer concerts held outdoors on summer evenings by the water and beautiful Burton chase park the season starts July eleventh with opera.

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