William Barnhart

The combination of those, having them on land and then having them close to major population centers, as we're starting to see, is proving to be absolutely devastating.

These were extraordinarily powerful earthquakes.

A 7.2 earthquake alone would be a catastrophic earthquake in this region, but to immediately follow that only 39 seconds later by a 7.5, that's about three times more powerful than...

That 7.2 earthquake leads to a really dire situation.

These earthquakes, of course, are so dangerous because not only do they cause intense shaking, but they occurred very close to population centers.

At this time right now, we don't yet know if there was a surface rupture.

So did they come up to and break the surface of the earth?

I would say it's probably likely given the style of faulting and where these occurred.

But that's something that myself and my colleagues in the U.S.

Geological Survey are actively looking into because that plays a very important role in assessing what the impacts of this earthquake are.

The closer the earthquake is to people and to population centers, both in terms of distance along the face of the earth, but as well as

depth within the earth, the more damaging it can be.

That is still absolutely a possibility.

Aftershocks are occurring and they will continue to occur for months to beyond a year for these earthquakes.

Some of those aftershocks could themselves be quite large and damaging.

there is always a very small possibility that an even larger or a similarly sized earthquake could happen it's an unlikely case but it is a possible case fortunately as time goes on the possibility of those large and frequent aftershocks decreases but people who live in that area or people who are responding to that area should understand that

Aftershocks are happening and they will continue to happen and people are likely to feel those aftershocks.

That's always a possibility, and that's why it's important for people who live in these areas to take the advice of local officials on when they should reoccupy structures, when they should reenter, or when they should stay away.