Earthquakes Galore!

Dominic Hall-Thomas

Dominic Hall-Thomas- Yesterday New Jersey was hit by the latest in a series of small earthquakes, or aftershocks. They stemmed the 4.8 magnitude earthquake that shook New York last month. It was the largest earthquake to hit the tri-state area since 1973. 

Scientists around the area have continued to monitor the activity. I spoke with a seismologist to see if we are in store for more earthquakes. 

Raymond Russo, you're an associate professor of geological sciences at the University of Florida. So you must be used to studying larger earthquakes than the one we've just had in New York a few weeks back. Tell us, is it unusual to have earthquakes in this part of the U. S.? 

Raymond Russo- It's actually not very unusual. They're quite Frequent small magnitude earthquakes all up and down the eastern seaboard. They are usually not felt. They don't cause damage. The truth of the matter, though, is that the population of earthquakes with regards to magnitude is like a pyramid. 

So at the low end of magnitude, there are many, many, many events.  But those many events  are telling us that there's always the possibility of larger magnitude earthquakes. It's rare, but it does happen. 

Hall-Thomas- We have continued to see smaller earthquakes or aftershocks, in New Jersey, the most recent,  was yesterday.  Is that pretty common for them  to continue going on for, you know, almost a month? Would people have even felt it? 

Russo- Generally not. I think it's a little bit. More rare for smaller earthquakes to have an aftershock series, but certainly big earthquakes will have aftershock series that can go on for, even a year.

So, basically, if you think about what's happening here, the earth has moved suddenly on some kind of fault plane, and so areas that have slipped relaxed stress, but areas that have only partially slipped  haven't quite done all their work. And so you can think about that as kind of the aftershock series happening because there's just a little bit more stress that needs to be released. And therefore, we get this earthquake. 

There's always a possibility that it's actually leading to get another even bigger earthquake.  In which case, the things that we're calling aftershocks all become foreshocks.  I would suspect that if this goes on much longer, um, people would start to get a little bit more concerned about exactly that possibility. But again, you know, the aftershocks that are happening here. Do seem to be slowing down and the magnitude are small. So, probably not 

Hall-Thomas- How do people start predicting them? And can we predict some coming up in New York? 

Russo- Here's the thing. So many different phenomena will affect the levels of stress on the earth. We're limited to very near the surface of the earth in our observations. The faults are deep or deeper. than we can usually get to. It is extremely expensive to do fault monitoring. Because there's just, there's just so many factors involved. 

Yes. You need to dedicate lots of equipment to a permanent location on the ground in a place where you don't know  that an earthquake is going to happen.

What we can do is we Have a reasonably good idea of where these major faults are. We can  then predict reasonably well how big of an earthquake is this  fault system is likely to produce.  And then engineer your buildings, educate your population to withstand to be resilient in that kind of shaking.

Hall-Thomas- So you think it's unlikely the residents in New York and New Jersey will have to do much kind of altering of their homes  to plan for earthquakes in the future?

Russo- I doubt that there would be a significant effort in upgrading current infrastructure in the area. On the other hand, everybody can. Do the minimum preparation For example, many people are injured in an earthquake because something in the home falls on them. Right? Having moved lots of books recently, you don't want the bookshelf falling on you.

Hall-Thomas- Raymond Russo from the University of Florida. Thanks for joining us. 

Russo- Thank you very much. I've enjoyed talking to you.