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Magnitude 6.3 Earthquake in Central Italy

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Early this morning, April 06, 2009, a magnitude 6.3 earthquake struck near Rome, Italy.

We spoke with Stuart Sipkin, a geophysicist at the USGS National Earthquake Information Center to fill us in on the details.




Public Domain.



[Intro Music]

Scott Horvath: Welcome! And thanks for listening to the USGS CoreCast. I’m Scott Horvath. Joining me on the phone right now is Stuart Sipkin, a Geophysicist at the USGS National Earthquake Information Center. We’re going to be talking to Stuart about the Magnitude 6.3 earthquake that happened this morning in Central Italy.

There’s been a lot of buzz sent around this morning regarding this earthquake between media and news coverage and also a lot of the traffic happening on sites like Twitter, etcetera. So can you tell me a little bit about what happened today?

Stuart Sipkin: Yes, there was a – as you said there was a magnitude 6.3 earthquake in Central Italy. It was a strong earthquake so it was pretty widely felt. It was felt pretty much throughout the whole country of Italy but strongly in Central Italy. And we are now getting reports of damage and the like from there but they’ve been sort of slow coming out because it did happen in the middle of the night.


We did know however that there was going to be quite an impact from this earthquake because of the PAGER System that we have running at the USGS National Earthquake Information Center where we can take our estimates of ground shaking and basically overlay that on a population density map and estimate how many people are exposed to that shaking. And we could see that a lot of people were exposed to strong ground shaking. So this is not unexpected.

Scott Horvath: So, how long did the earthquake actually last and how wide, you mentioned the PAGER System, how widely was the earthquake felt?

Stuart Sipkin: Well, it was felt pretty much throughout Italy. We have reports of people feeling the earthquake pretty much throughout the whole country, although the strong ground shaking was pretty much centered on Central Italy basically from about Rome on the West Coast up through to the Adriatic Sea.


Scott Horvath: Okay, and how long did the shaking last?

Stuart Sipkin: That’s kind of a hard question to answer. The duration of ground shaking depends on where you are. In other words, if you’re on a hard rock sate, it doesn’t last as long as if you’re in a sediment filled valley. So that particular question is unlike magnitude where earthquake only has one magnitude…

Scott Horvath: Right.

Stuart Sipkin: Duration of shaking depends on where you are.

Scott Horvath: And the geology, everything involved with that. Excellent! Okay, so did the quake itself occur in any known fault lines?

Stuart Sipkin: Yeah, running down the Central Spine of Italy. It’s a very mountainous area and it’s well known earthquake zone. It’s a very highly seismically active area and so that whole area has lots of faults running through it.


Scott Horvath: I read there’s multiple plates that are pushing up against each other and they create different types of fault. So I mean, like you said it’s a very complex area so…

Stuart Sipkin: Yes, this area is predominantly a bunch of micro-plates. It’s not a simple situation like say on the Coast of California where you have the San Andreas Fault System with one plate just sliding past another or say in Indonesia where you’ve got a subduction zone with one plate sliding underneath. In this area, because of Africa and Europe basically being a collision zone in there as they move toward each other. It’s highly fractured and broken up and it’s not a simple situation with just a couple of plates interacting. There are a lot of micro-plates and they’re interacting in different ways as they move around and you can expect all kinds of different fault motion and…


Scott Horvath: Right.

Stuart Sipkin: This particular earthquake and this particular fault zone tend to experience what we call “extensional earthquakes.” But you can have all different kinds of earthquakes because of the complexity.

Scott Horvath: Now, is there anything else that you’d like to add before we end this podcast?

Stuart Sipkin: Well, I’ve already mentioned PAGER and that’s been a very important tool because this earthquake happened in the middle of the night in Italy and so reports tends in that sort of situation to start coming at daylight. The reports of damage and injuries and the wake probably would have been a lot faster if it happened during the day. And a lots of times we have earthquakes in areas where communications are not good to begin with. And so PAGER has really been a very valuable tool in our being able to assess the likely impact of an earthquake and so basically mobilize our resources in order to report on those effects.


Scott Horvath: Great! Well, Stuart I appreciate your time this morning. Hopefully will keep an eye out on for more information to follow up with whatever happens related to this earthquake event.

Stuart Jipkin: Yes. 

Scott Horvath: Appreciate it. Thank you very much.

Stuart Sipkin: Thank you.

Scott Horvath: And that does it for this episode of the USGS CoreCast. Thanks for listening. And don’t forget as I mentioned, you can visit for more information related to this earthquake and other earthquakes with maps, resources, the PAGER System information that Stuart mentioned and many others.

CoreCast is a product of the U.S. Geological Survey Department of Interior. Until next time, I’m Scott Horvath saying, “Keep it cool.”

[Ending Music]

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