Welcome, and thanks for listening to the USGS CoreCast.
I'm Scott Horvath.
Earlier this morning, there was a 7.8 earthquake that rattled the city of Chengdu in eastern
Sichuan China.
Joining me on my phone today,
Dr.
Harley Benz, he's a scientist in charge with the National
Earthquake Information Center, with the USGS.
Harley, thanks for taking the time out of your busy morning to speak with us today.
Good morning, and you're welcome.
So can you tell us a little bit about the major earthquake that occurred in China this morning?
Yes, there was a magnitude 7.8 earthquake.
It occurred about 90 kilometers or 55 miles west of Chengdu, China,
a city with a population of more than 2 million people.
The earthquake was big enough that it was felt throughout the region.
It was felt as far away as Pakistan, Thailand, and Vietnam.
So are earthquakes in this area of the world,
or in the area of China,
uncommon?
No, no.
This is an area that has experienced in the past damaging earthquakes.
The most recent damaging earthquake in this area was a magnitude 6.1 earthquake in 1989,
And there was a magnitude 7.5 earthquake in 1933 that caused more than 9,000 casualties.
So earthquakes in this part of China are infrequent, but not unexpected.
Okay.
Now, do you know if this particular quake occurred on a known fault or on a known fault
structure?
Well, this is an area that has active seismicity.
There's a large basin to the east of this earthquake,
it's the Sheshwan Basin.
And the basin is a fault-controlled basin,
the faults are along the northwest and western
side of the basin.
And we think that this earthquake occurred on the Longsmanshan Fault or a tectonically
related fault, which is a basin-bounding fault.
Now, obviously there's a lot of information coming out of this,
about this earthquake.
Where can the public go to get more information on this particular quake?
The public should go to earthquake.Usgs.Gov.
This is the main USGS portal for
earthquake information.
If you go to that main page up in the upper left hand
corner of the website, you'll see a link to the magnitude 7.8 Eastern Szechuan
earthquake.
When you click on that link,
you'll go to a series of pages that have a variety
of maps and other kinds of content on the historical seismicity,
the geology, and information
about what people felt in the area,
how many people reported what they felt,
the intensity
that the reported but also what people can find there is information on on how
many people were likely exposed to severe or strong shaking these can be
found on the links to a product that the USGS produces called pager prompt
assessment of global earthquakes for response and there you'll find a map
showing the prediction of the ground shaking based on the stuff that we've
done superimposed on the population of the area.
And when you combine the two, you
can get information on the number of people
exposed to severe ground shaking or moderate ground shaking.
And for this earthquake, there was large numbers
of people that were exposed to severe shaking.
And consequently, there's likely damage from this earthquake.
Wow, and all that information is available on the earthquake website through these maps
right now, right?
That's right.
Great.
Excellent.
Well, is there anything else that you would like to add that I didn't already ask you?
Yeah.
For this earthquake, because of its size,
we should expect to see lots of aftershocks.
Often the media will ask us,
or the public will say, well,
how long will we feel earthquakes
and how big will they be?
Right.
In the first few hours following the magnitude 7.8,
we've recorded more than 13 earthquakes,
the largest being a magnitude 6.
The earthquakes are being located along a northeast trending fault,
and they extend over
a region about 100 kilometers or 60 miles,
which is consistent with the size of this
earthquake.
In terms of the total number of aftershocks,
aftershocks from an earthquake typically of
this size will be occurring weeks and months from now,
but typically with time, the number
of earthquakes will go down and the size of the earthquakes will go down,
but there are
chances of having other large damaging earthquakes as part of this sequence occurring in the
next few days and weeks there is a potential for that.
Well great Harley
thank you very much for providing us with all that great information and
thanks for joining us this morning on the phone.
You're welcome.
And that does it
for this episode of the USGS CoreCast.
Thanks for listening and don't forget to
visit our website at usgs.Gov slash CoreCast where you can find more
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Geological Survey, Department of the Interior.
Until next time, I'm Scott Horvath saying, keep it cool.