Estimating the likelihood of an earthquake

Earthquakes are a powerful force of nature, but nature isn’t always responsible for causing earthquakes. Some earthquakes are man-made. A new type of 3D software can now help estimate the likelihood of these man-made earthquakes. We go inside the lab at San Antonio’s Southwest Research Institute to learn more.

TRANSCRIPT

Earthquakes are a powerful force of nature, but nature isn't always responsible for causing earthquakes.

Some earthquakes are man-made.

A new type of 3-D software can now help estimate the likelihood of these man-made earthquakes.

We go inside the lab at San Antonio's Southwest Research Institute to learn more.

It's a common effect when you produce oil and gas that you co-produce water.

And then, so you split that.

You take the economically valuable material, the oil and gas, and you take that away.

And then you have the problem of disposing of the excess water that you've just produced.

It's very common to get that back into the ground by re-injecting it.

And typically, it's re-injected into horizons that are porous and permeable.

In other words, they're able to accommodate that fluid being injected back into it.

'Cause oil and gas companies do a lot of -- put a lot of money into understanding where faults are.

And they don't want to waste their time injecting fluids into faults.

They don't want to waste money injecting fluids into faults when that could damage their reservoir.

Or it could produce problems with other wells nearby.

So they want to, when they're injecting, they want to have a good bang for their buck.

They don't want to waste money and resources.

And the other aspect is that if they are disposing of fluids that need to be injected into the ground, they can evaluate the potential of that site for its ability to generate an earthquake.

So they can do a -- again, it would be a pre-activity simulation to see if that site is likely to produce earthquakes that might be either damaging or felt at the surface of the earth.

This provides a way of parameterizing those problems and saying, 'Well, we may have a problem here.

So we need to think about reducing the pressures, the volumes that we're injecting.

We may want to move the well site to somewhere else because it's not a good location.'

Or we could say, 'Looks good.

We should be fine.'

Now we have this software.

It's an integration of structural geology and hydrogeology, with a little bit of seismology on the side.

So what we've tried to do is get the best we can in terms of analytical solutions to these situations.

And combining these things gives us a way of understanding the likelihood of induced seismicity based on what we know about pressure effects in the earth and size and orientation of pre-existing faults.

North Carolina's Great Smoky Mountains National Park is home to rare fireflies that can synchronize their flashing-light patterns.

Six flashes at a time, at first independently, then in unison, make up an elaborate mating dance that can only be seen for two weeks each year.

Here's a look.

There is no place on Earth in a temperate climate that is the size of Great Smoky Mountains National Park that can match the rich biodiversity found in the park.

So, having all of that variety of different habitats allows you to have great places for a wide diversity of animal species to live, plants and animals.

And we are continuing to discover just how great that diversity is in the park.

And to date now, in 2016, we have over 20,000 recognized species in the park.

And even more impressive, 900 of those species are newly discovered to science.

And for two weeks every June, for only about two hours in one small corner of the park, one of those rare species creates a kind of nocturnal magic.

And it's all about love.

The firefly display is -- yeah, it's all about courtship.

And it's their way of finding each other and recognizing that they're -- it's the same species.

This is the synchronous firefly.

This is what the firefly's display looks like in a time-lapse still photo using a wide-angle lens.

You can see the blanket of light across the forest floor.

This is what it looks like on video.

We've brightened the video just a bit to help you see the fireflies.

Just keep watching.

As more and more fireflies rise up from the ground where they live, they will light and gradually synchronize their flash, linking together on and off, on and off, all together.

And so the male will be primarily the one that you will see flashing.

It does six to eight flashes and then a period of darkness.

And then it flashes again and keeps repeating that pattern.

The female will be on the ground and will respond with a double flash.

And then when they find each other, they can reproduce.

And then they don't live much longer after that.

So their primary role as adults is to reproduce.

Becky Nichols is the entomologist for Great Smoky Mountains National Park.

She's recorded 19 species of fireflies living in the park, including But it's the only one of the few firefly species in the world that synchronizes its flash pattern.

And the park's synchronous fireflies weren't discovered until 1994.

So, all fireflies have a different pattern of flashing.

And so in order to recognize each other in the dark, they have to have a specific pattern for that species that they can each recognize.

Some fireflies soar at different heights above the ground.

Some fly in a specific flight pattern.

The common evening firefly repeats an upside-down J pattern.

But the synchronous firefly doesn't have a pattern.

Its flash sets it apart.

And like all fireflies, that light is created through a process called bioluminescence.

I don't know if you can see these couple segments here that look a little bit lighter.

That's where the light production occurs.

It's a chemical reaction.

And it's incredibly efficient -- lots of light, no heat.

Fireflies combine the chemical luciferin with an enzyme called luciferase in the presence of oxygen.

When all three are combined in the firefly's abdomen, light is produced.

Every time the firefly flashes, a little more of the chemicals are mixed.

They don't feed as adults.

So what they have in reserve is all they're going to have.

And so once they do their flashing behavior and reproduce, then that's the end of their life span.

[ Insects chirping ]

It's a sad story in a way.

But it's also beautiful.

And it makes the Smoky Mountains even more of a treasure.

And that wraps it up for this time.

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Until next time, I'm Hari Sreenivasan.

Thanks for watching.

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