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What we know about the Venezuela earthquakes · DEEP INSIGHT

• 0:02
  Speaker 1: With some breaking news to bring you at this sour.
• 0:05
  Speaker 1: Two earthquakes have hit near Venezuela's capital, Karakas.
• 0:09
  Speaker 2: Earthquake shoot the entire building minutes ago.
• 0:15
  Speaker 1: The elevator story moving really fast and shake in side
• 0:18
  Speaker 1: to side and just going all the way.
• 0:20
  Speaker 3: Back at my back one of the buildings that collapses
• 0:23
  Speaker 3: here in Karakasa. Those two earthquakes were apart, just thirteen
• 0:29
  Speaker 3: and nine seconds apart.
• 0:35
  Speaker 4: So back to back earthquakes have hit Venezuela. Experts say
• 0:39
  Speaker 4: the number of casualties could well rise to thousands of
• 0:42
  Speaker 4: the extent of the damage becomes clear. We'll tell you
• 0:45
  Speaker 4: what happened and why, but first, this footage from the
• 0:49
  Speaker 4: outskirts of Krakas, filmed by a content creator, gives you
• 0:52
  Speaker 4: just a real sense of what the aftermath was really like.
• 1:00
  Speaker 2: H how do you go? You are? Are are? What
• 1:15
  Speaker 2: are you? How are you go? Where do you go?
• 1:32
  Speaker 4: You get a real sense there of the panic, the
• 1:35
  Speaker 4: chaos on the streets after the quakes. It was similar
• 1:38
  Speaker 4: inside the airport in Caracas.
• 1:40
  Speaker 5: Have a look.
• 1:57
  Speaker 4: Well, that footage gives you an idea of the chaos
• 2:00
  Speaker 4: after these quakes. And Vanessa Herreros is in Caracas and
• 2:03
  Speaker 4: she centers the latest on the rescue efforts.
• 2:07
  Speaker 3: We are the municipality of Chakao, one of the worst
• 2:11
  Speaker 3: areas that were affected by the two earquakes that skid
• 2:15
  Speaker 3: Venezuela on this Wednesday. At my back we can see
• 2:19
  Speaker 3: one of the buildings that just collapses in this area.
• 2:22
  Speaker 3: This is a sensitive part of Karakas for airquakes because
• 2:29
  Speaker 3: from here is the tectonic fault cross this area. During
• 2:35
  Speaker 3: the earthquake in ninety sixty seven, this area of Tarakas
• 2:39
  Speaker 3: one was the most affect that many buildings collapses here
• 2:43
  Speaker 3: then and now at least ten building has collapsed in
• 2:48
  Speaker 3: Karaka City according to the authorities. But the most affected
• 2:53
  Speaker 3: area is Laguayra State Estate, which is just at the
• 2:58
  Speaker 3: north side of Caa that gas Rigezi here Maginari removing
• 3:04
  Speaker 3: the concrete the rubber um trees looking by trying to
• 3:11
  Speaker 3: look for survivors.
• 3:13
  Speaker 4: Well, that was Anna Vdessa Herrero in Venezuela's capital. So
• 3:16
  Speaker 4: exactly where did these two quakes hit and how strong
• 3:20
  Speaker 4: were they?
• 3:21
  Speaker 6: The back to back earthquakes hit the South American nation
• 3:24
  Speaker 6: of Venezuela, which borders Brazil and Colombia.
• 3:27
  Speaker 7: The capital is Caracas, which was badly hit, although the
• 3:30
  Speaker 7: epicenter was to the west of the capitol.
• 3:32
  Speaker 6: Rescuers are searching the rubble in Caracas and the state
• 3:35
  Speaker 6: of Laguara.
• 3:36
  Speaker 7: Where the UN stays. More than one hundred buildings have collapsed.
• 3:39
  Speaker 6: One survivor described the scene as like a horror movie.
• 3:43
  Speaker 7: The first quake had a magnitude of seven point two.
• 3:45
  Speaker 6: And struck at four minutes past six in the evening
• 3:48
  Speaker 6: local time.
• 3:49
  Speaker 7: Less than a minute later the second hit. This was
• 3:51
  Speaker 7: stronger seven point five in magnitude.
• 3:54
  Speaker 6: The strongest earthquake to hit Venezuela since nineteen hundred.
• 3:59
  Speaker 4: Well, our senior climb and science reporter, as we sell
• 4:01
  Speaker 4: out as with us to explain more and as we
• 4:04
  Speaker 4: how unusual are back to backquakes under a minute apart.
• 4:09
  Speaker 1: Well, normally we get the main earthquake and then we
• 4:11
  Speaker 1: get a series of aftershocks. But actually these two earthquakes
• 4:14
  Speaker 1: together formed the main shock. It's quite an unusual phenomenon
• 4:18
  Speaker 1: called a doublet sequence. It's less unusual in this part
• 4:21
  Speaker 1: of the world. They actually had one in twenty twenty five,
• 4:25
  Speaker 1: but it represents quite the complex techtolic nature of the
• 4:28
  Speaker 1: plates over in that area, and so what happened effectively
• 4:31
  Speaker 1: is a bit like ripping a piece of paper. Sometimes
• 4:33
  Speaker 1: you get a straight line and sometimes it radiates out,
• 4:36
  Speaker 1: and that's where you're getting that stress dissipate and so
• 4:39
  Speaker 1: less rare for this area, but quite rare for this
• 4:41
  Speaker 1: part of the world. And both of those were very
• 4:44
  Speaker 1: significant earthquakes.
• 4:45
  Speaker 4: As we stay with us because one of the most
• 4:47
  Speaker 4: asked questions following these quakes is what causes an earthquake?
• 4:52
  Speaker 5: Well, here's the answer.
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  Speaker 6: The Earth is made up of different layers.
• 4:56
  Speaker 7: At the center is the care around that is the mantle,
• 5:00
  Speaker 7: and on the outside is the crust.
• 5:01
  Speaker 6: The Earth's crust is cracked into different pieces called plates.
• 5:05
  Speaker 7: These plates are very slowly moving and shifting around. And
• 5:09
  Speaker 7: where the two plates move forward towards each other, you
• 5:11
  Speaker 7: can find the most powerful earthquakes.
• 5:13
  Speaker 6: Friction causes pressure to build up until it becomes so
• 5:16
  Speaker 6: great that it is suddenly released as a shock wave.
• 5:19
  Speaker 6: This is the earthquake.
• 5:21
  Speaker 7: Matthew Winegarson from San Diego State University explains more.
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  Speaker 8: Earthquakes typically happen on faults. Faults are deep fissures in
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  Speaker 8: the ground or cracks where motion between two rocks on
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  Speaker 8: either side of the fault can occur like a rubber band,
• 5:38
  Speaker 8: where in any given year, you're sort of pulling that
• 5:41
  Speaker 8: rubber band apart slowly, and eventually you get to the
• 5:44
  Speaker 8: point where the rubber band doesn't move anymore, won't stretch anymore.
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  Speaker 8: An earthquake happens right at the point where you would
• 5:51
  Speaker 8: stretch it just a little bit more and that rubber
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  Speaker 8: band would break.
• 5:55
  Speaker 9: Well.
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  Speaker 4: A really good visualization there from Matthew. Many of the
• 5:59
  Speaker 4: online search is asking why so many earthquakes today? That's
• 6:03
  Speaker 4: because Japan and California also had earthquakes. This is Japan,
• 6:07
  Speaker 4: where there was a strong seven point two tremor off
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  Speaker 4: the northern coast. No major damage or injuries were reported there.
• 6:14
  Speaker 4: Japan is one of the world's most seismically active countries,
• 6:19
  Speaker 4: sitting on top of four major tectonic plates. Whilst a
• 6:23
  Speaker 4: rural area of northern California experience its strongest earthquakes since
• 6:27
  Speaker 4: nineteen forty, but it caused only mild shaking, with no
• 6:31
  Speaker 4: immediate reports of damage or injuries there.
• 6:35
  Speaker 5: So ESMI, let me bring you back in. Is this
• 6:37
  Speaker 5: usual or unusual?
• 6:39
  Speaker 1: This is actually quite usual. It might come as a
• 6:41
  Speaker 1: surprise to people. We actually get millions of earthquakes every year,
• 6:44
  Speaker 1: most of them we can't feel. But the US Geological
• 6:47
  Speaker 1: Survey measures about thirty thousand earthquakes it considers to be significant,
• 6:52
  Speaker 1: and it can pick up that movement. I think normally
• 6:54
  Speaker 1: when you get very big events like this in Venezuela,
• 6:57
  Speaker 1: people are a lot more aware of other earthquakes happening
• 7:00
  Speaker 1: around the world. There is some evidence that where you
• 7:03
  Speaker 1: get quite significant earthquakes, stress can be dissipated, and where
• 7:07
  Speaker 1: there's weak fault lines, as we heard in that video,
• 7:10
  Speaker 1: other earthquakes can be triggered. But that's normally quite localized.
• 7:13
  Speaker 1: You wouldn't get, for example, this earthquake in Venezuela triggering
• 7:16
  Speaker 1: one in Japan, and Worth pointing out that the one
• 7:19
  Speaker 1: in Venezuela was given this sort of red alert. That
• 7:22
  Speaker 1: one in Japan, although given a very high number in
• 7:25
  Speaker 1: terms of how big it was, actually got a green
• 7:27
  Speaker 1: alert because it was offshore, not near people. So far
• 7:30
  Speaker 1: more earthquakes happening all the time beneath our feet, and
• 7:34
  Speaker 1: most of them you don't really notice.
• 7:36
  Speaker 4: We'll come back to the numbers in a moment. In Venezuela,
• 7:39
  Speaker 4: the rescue operation continues. These pictures are from one of
• 7:42
  Speaker 4: the worst hit areas north of the capital. The US
• 7:46
  Speaker 4: Geological Survey says thousands of people could have been killed
• 7:49
  Speaker 4: in total. Well asks me about their estimates in a moment.
• 7:53
  Speaker 4: But the recovery from the quakes is also a big
• 7:56
  Speaker 4: test for President Trump since the US military intervention there
• 8:00
  Speaker 4: in January when the former dictator Nicholas Maduro was abducted
• 8:03
  Speaker 4: and flown to the US. Venezuela has been heavily dependent
• 8:07
  Speaker 4: on the decisions taken far away in Washington. So what
• 8:12
  Speaker 4: is the US actually doing. He's their top diplomat, Marco Rubio.
• 8:16
  Speaker 9: They have a much of collapsed buildings and so they'll
• 8:19
  Speaker 9: need a lot of help in terms of digging through that.
• 8:21
  Speaker 9: The airport there is badly damaged, so we'll have to
• 8:23
  Speaker 9: rely on the Department of War to deploy assets there.
• 8:26
  Speaker 9: And then we're also hopping them with some overhead imagery,
• 8:29
  Speaker 9: especially in coastal areas where they don't have full visibility
• 8:32
  Speaker 9: over what the damage has been or what the impact
• 8:34
  Speaker 9: has been.
• 8:35
  Speaker 5: Well, that was Marco Rubio.
• 8:36
  Speaker 4: Let's go back to as me and how is that
• 8:39
  Speaker 4: estimated death toll we mentioned actually calculated so the.
• 8:43
  Speaker 1: US Geological Serve uses something called a pager system when
• 8:47
  Speaker 1: they start to get data in an earthquake has occurred.
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  Speaker 1: What they're looking at is how strong it is. They're
• 8:52
  Speaker 1: looking at how close the surface it is, because the
• 8:54
  Speaker 1: closer is the more ground shaking you get. They also
• 8:57
  Speaker 1: look at the concentration of population, compare all these characteristics
• 9:01
  Speaker 1: to previous earthquakes to give us an estimate of the
• 9:04
  Speaker 1: potential death toll. So when this first occurred, they were
• 9:08
  Speaker 1: estimating that it was around a forty four percent risk
• 9:11
  Speaker 1: that there could be loss of life between ten thousand
• 9:13
  Speaker 1: and one hundred thousand people. Now it's important to point
• 9:16
  Speaker 1: out that could come down considerably or it could go up.
• 9:19
  Speaker 1: So the question is why do you issue this warning
• 9:21
  Speaker 1: when you don't actually know the death toll. The reason
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  Speaker 1: the US Geological Survey does this is it really helps
• 9:27
  Speaker 1: emergency service responders, it helps governments, and it helps media
• 9:31
  Speaker 1: to prepare for this. So we've already heard today that
• 9:34
  Speaker 1: Venezuela's called on other countries for their support. The UN
• 9:37
  Speaker 1: is looking at bringing in people to support them as well,
• 9:40
  Speaker 1: so it's all part of the rescue effort. Is a
• 9:42
  Speaker 1: reason they issue that figure that actually the real death
• 9:44
  Speaker 1: toll will start to see in the coming days.
• 9:47
  Speaker 4: One final question, because these quakes, as we've been saying,
• 9:50
  Speaker 4: they had magnitudes and seven point two and seven point five,
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  Speaker 4: we've had a lot of questions asking about how earthquakes
• 9:57
  Speaker 4: are measured and what are the biggest ones.
• 10:00
  Speaker 1: So this particular scale that is used as a logarithmic scale,
• 10:04
  Speaker 1: so that means that each number you go up, it
• 10:06
  Speaker 1: gets ten times bigger. So as an example, if you
• 10:09
  Speaker 1: had a six magnitude earthquake in vers the five, the
• 10:11
  Speaker 1: six would be ten times bigger. If you had a
• 10:13
  Speaker 1: seven versus a five, it would be one hundred times bigger,
• 10:16
  Speaker 1: for example. So getting close to seven is pretty significant.
• 10:19
  Speaker 1: But the largest earthquakes that have ever been recorded have
• 10:22
  Speaker 1: been up in the orders of nine, so that's one
• 10:25
  Speaker 1: hundred times bigger than what we saw today. The biggest
• 10:28
  Speaker 1: ones we've seen was a great Chilean earthquake back in
• 10:31
  Speaker 1: the nineteen sixty which is a nine point five. A
• 10:34
  Speaker 1: few years later in Alaska was a nine point two.
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  Speaker 1: But the one probably most people actually remember was more
• 10:39
  Speaker 1: recently the two thousand and four earthquake and Sumatra, which
• 10:42
  Speaker 1: is a nine point one and result in that devastating tsunami.
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  Speaker 1: So it's that secondary effect that resulted in such significant loss.
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  Speaker 5: Of life Aswei.
• 10:50
  Speaker 4: Thanks very much, and that is all you need to
• 10:53
  Speaker 4: know about the earthquakes in Venezuela.