Washington Landslide A Wake-Up Call About Threat Of Natural Disasters In San Diego
MAUREEN CAVANAUGH: This is KPBS Midday Edition, I am Maureen Cavanaugh. Our top story on Midday Edition, the extent of the landslide tragedy in Washington state continues to unfold, as of today officials say twenty-nine bodies have been recovered from this steelhead drive community in the town of Oso, another twenty people are still reported missing. There are not many comparisons to be drawn between the heavily forested and rainsoaked region of Washington and usually sunny San Diego, but fire and rain have also undermine some hillsides in our region and as happened in oh so, that many people seem to take the threat of national ñ natural disaster seriously. But like to welcome my guest Pat Abbott, then you state University professor emeritus, but back to the program. The pictures of website are devastating, the recovery effort is going on through 20 to 50 feet of mud in some sections, as is one of the worst landslides in US history? PAT ABBOTT: Yes it is terrible and it is in an area where the landslides are very common and in fact, this landslide itself is a portion of an older landslide in the 1930s side ninety-two; his landslide. MAUREEN CAVANAUGH: Their conflicting reports about whether people in that committee were warned about the dangers of living so close to her repeated slide area, was there any way to predict some like this was going to happen again? Was that a virtual certainty? PAT ABBOTT: This is very much like the story we talk about with earthquakes in Southern California. We tell you what will happen and well they will occur, we don't know when. Since the same thing here, is an area of large landslides and there are larger landslides and that right next to it, we know they're going to be landslides there and we don't know when. MAUREEN CAVANAUGH: Is there a time frame given for landslides? PAT ABBOTT: On this one, not a timeframe but we had the pineapple express, we get asthma. ñ Atmospheric rivers and water, they had over 200% the normal amount of rain caught me find you can if predict when that will occur but when you do that you can add weight to the slope and make the pull of gravity stronger and given that, you say certainly the odds are higher now but that does not mean it's going to occur when it did. MAUREEN CAVANAUGH: There are some are quotes that a report that a small earthquake that triggered landside duty that is for the cause? PAT ABBOTT: I don't, it was a 1.1 about 12 miles away, that is a very small event, what we're looking at here is the immediacy of the rains fall and the soaking and we look at pictures and you see that huge bend in the river, what is happened to be a hillside, let's go over the decades. If you take a landslide to look at a photo now against the Hill, CA woken up mass of rock against the hill and that is the retaining wall or buttress now and is the river going to do that ñ the river will start a running away as we go on time and remove support in the hillside and were working towards the next big landslide, with those conditions if I have to put a finger on something I would put it more on the pineapple express than on the very tiny earthquake some distance away. MAUREEN CAVANAUGH: Is there anything humans can do to help an area like that get sturdier in a shorter period of time? PAT ABBOTT: That area so common from landslides in that exact spot, they went in here in 2006 and build a rock wall to try to hold back the hillside, and that itself was overrun by a small landslide and they started trying to take and reroute the river, at the egg river and it rerouted itself again and some attempts were made that Eastern getting a problem of spending more on measures to protect the house then the houses are worth? It's a difficult question. MAUREEN CAVANAUGH: What about logging activity that was happening just above the landslide site? PAT ABBOTT: One of the worst things about logging would be soiled unprotected and those tree roots are not the things that were holding the hell up, you look at the slides of the slide back there the trees themselves their roots are not going down very far in other words, those are smaller scale things kind of like in the 1.1 earthquake, everything adds up that some things are big factors. MAUREEN CAVANAUGH: After rains in areas burned by wildfire, how different was the landslide in Washington to the kinds of what landslides that we see here? PAT ABBOTT: Very different, this light up there was actually to the vans and that was only made clear, when you look at the debris field being picked over, here is the mud that they set foot out like a tsunami, that event occurred and when that clay rich mud flowed out and did all that damage and death, that remove support from the hill and then the big Sandy mass came down, those are two events separated by four minutes, the point is we do not have those kinds of clays. We don't have those kinds of sands that collapse, that is glacial debris and if we go back a few thousand years that area had a ice dam over the valley and you're looking at mud and loose sands deposited in that glacial Lake, glacier dams are long gone and the river cuts through it but you basically very loose sediments and GUI, sticky Lake clays and we do not have that sort of situation. I don't mean that we don't have problems but I can imagine anything here so catastrophic. MAUREEN CAVANAUGH: We have similar problems of people living near or unstable hillsides? PAT ABBOTT: Yes we do, having said that the property damage can still occur here and back in 2007 going up my salute at going back even farther in the early 1980s when we had strong El NiÒo, they say there's another El NiÒo holding but I don't care about per se, is it a strong El NiÒo? We're talking about double annual rainfall that could mean something, if we go back to the early 1980s there are clay rich and sticky sediments on steep slopes, and we had homes destroyed in Rancho Bernardo, power way, I can keep going on but we do have unstable substrate in some areas and they cause this to happen. So it was most visible, didn't threaten lives are destroyed houses, that is the thing that we get, and not on par with what happened in Washington. MAUREEN CAVANAUGH: Obviously from what you're saying, there is a lot that is known about where the potential risks are and when it risky situations are developing, I am wondering what your impression is. Are the warnings that sentence make about in natural disasters and geological ones that can be predicted per se, know exactly when they will happen but there are likely to occur, with the taken seriously enough? PAT ABBOTT: I don't think scientists indicate well with politicians and politicians have semi-pressures on them, I don't envy their existence existence when so many groups want their issues taken care of. Then we can trust a couple of things here, for San Diego landslides that we were just talking about those are in cities and cities passed billing codes and we have these reviews before buildings are built, those are attempts to avoid these problems. For the earthquakes, every time you have a major earthquake in California we passed laws and change building codes, we have seen schools and hospitals get torn down and we respond, this area in Washington is a beautiful area. You would love to live there, that is an incorporated area unincorporated area, you don't see a strong government presence and that is a plus for a lot of people, they don't want people telling them what they can do and I'm sympathetic with that, but at the same time who is going to come in and tell them to do something? Is someone did come in and tell them to do it is that something that would look kindly on? It's complex. MAUREEN CAVANAUGH: Talking about earthquakes in California and San Diego and Southern California, last Friday we had a series of earthquakes that shook northern Orange County and the apparently were 100 moderate to small quakes in today time period, some reports called this a cluster, is that a proper term? PAT ABBOTT: Now, I would not use that term for this, I want something bigger than that. To me this was a lot of nice little for shocks getting up to 4.6 leading up to a main event which is a 5.1, now we're seeing the aftershocks, we always say you never have just one earthquake, a earthquake is a sequence of movements along a fault. Small ones don't catch the attention and we focus on the big ones, once one of these darts we do not know with a big was going to come. That's why you heard when the 5.1 they say was that the earthquake? They say weight seventeen ñ seventy-two hours and he could get a bigger one and we're still having after shocks that go on for weeks and months, that is a long section of fault going to little adjustments to relieve the strain energy it's a gimmick it is related. MAUREEN CAVANAUGH: But go with these of the San Andreas fault? PAT ABBOTT: Now, these are faults that have a compound of vertical movement in them and they point to Hills on the uphills along these group of faults. MAUREEN CAVANAUGH: As you said the strongest quake in this group of earthquakes measured 5.1 and it seemed to actually cause considerable property damage. I saw pictures with houses in a state of a mess, that's a strong earthquake though is it? PAT ABBOTT: If you just look at the damage and the red tag houses and asked me what the size of the earthquake was? Looking at this damage looking at the damage, I said 5.7. There is more damage than you'd expected I would attribute that two things, one it was very shallow, not very deep love the surface which means if you want to visualize it, it comes like an explosion metaphorically, if energy is near the surface when a person forth more of it is dumped on the surface and with that vertical component of movement more energy is driven upward onto the ground and those things magnified the health effects of the actual size of the earthquake. MAUREEN CAVANAUGH: When you talk about a sizable earthquake just last night there was he a .2 magnitude earthquake off of the coast of Chile, and five people died in that quake. Remind us white quakes in that area of the world are so much stronger than twit quakes we have in California? PAT ABBOTT: That gets us into plate tectonics, people have heard this many times but you take the earth looking like a hard boiled egg with the HL cracked into pieces, that is the other part of the earth, and those HL pieces are sometimes 62 miles thick and they do three things, pull away from each other, slide past each other, that is the San Andreas fault and the really big earthquakes are where those HL pieces collide and that is what happens here, 1162 mile thick one is pulled beneath another one and immense amounts of energy of all, the CE .2, that is just another class of earthquakes far bigger than we expect and only three of the 50 United States Ave. experienced magnitude 9 earthquakes and telephone is not one of them. MAUREEN CAVANAUGH: And we can't write? PAT ABBOTT: You can build of enough energy, it will be released before guesstimating 29. MAUREEN CAVANAUGH: Last time the major earthquake in Chile, I was talking to put on this program and you were telling me that we were comparing the loss of life as it were, with the Chile and Haiti, Chile's loss of life was so small compared to Haiti, considering the huge earthquake that they had. You said Chile compares very well for earthquakes? PAT ABBOTT: They do and as I've walked around I have been covering all of Chile and the good of homes built in the 1800s in this one thing that they did, they would take a basement that was 3 feet deep and cut down trees, but the big tree trunks in there and build the houses on it, sexy billing or house is not on the ground but on tree trunks that act as rollers, so there's vice isolation engineering concerts we're proud of now, there are Chileans doing it over 100 years ago. They were built that way to begin with. MAUREEN CAVANAUGH: There's also soon only danger after the quake, no real tsunami developed, why do some quakes trigger tsunamis and some don't? PAT ABBOTT: I was expecting something big there and when I walk around the Bay I did not feel comfortable because it's like an example of what tsunami means, overweight, I was expecting something bigger, but there is a thing where if we look at the magnitude of an earthquake and look at the twenty heels here, it the 5.1 does not tell you everything, let us jump back to 2004 in Indonesia. That is one that killed almost a quarter million people but when you look at where the water energy went is primary east and west, it's not really hit India or Bangladesh, so in other words what direction to the plates move? We get the directionality of energy and within the water column, the commonly talk about visualizing a tsunami like taking a rock and bring in the water and sing circles go out, and no, it's not that uniform, you get certain directions for far more energy is traveling than in others. MAUREEN CAVANAUGH: My last question, considering all of the geological activity that we have been talking about lately, do you think that Californians have become a little bit complacent about earthquakes? PAT ABBOTT: No, I don't I feel very encouraged. I've tried to help out with earthquake education for the efforts going on and I see an increased awareness and a lot of people and I really put a big emphasis on mental awareness, but we've been doing in schools for the last five years with the drop cover and hold on, I really love this program because I think by the time the kids go through from kindergarten to twelfth grade if you do and thirteen years of drop cover and hold on, that reminds me of the KTLA anchor with the 4.1, Isa jump, earthquake and went right under the desk, that is Will want people to do because that will minimize injury and death. MAUREEN CAVANAUGH: I want to thank you so much, I've been speaking with Pat Abbott, San Diego State University geology professor emeritus, thank you so much. PAT ABBOTT: Thank you.
The extent of the landslide tragedy in Washington state continues to unfold.
According to the latest update, officials say 29 bodies have been recovered from the collapse of the Hazel Slide in the town of Oso. Another 20 people are still reported missing.
San Diego State University Geology Professor Emeritus Pat Abbott said the mudslide was not a surprise to him. He said it happened in what is probably the most landslide-active place in the United States. What did surprise him however is how large it is and that it happened right next to a civilized area.
There are not many comparisons to be drawn between the heavily forested and rain soaked terrain of Northern Washington and usually sunny San Diego. But fire and rain have also undermined some hillsides in our region, and as what happened in Oso, not many people seem to take the ongoing threat of a natural disaster seriously.
Abbott said in San Diego, we're lucky in the sense that we don't have a specific area that's prone to landslide. The wildcard, he said, is an earthquake.
Additionally, he said a fierce El Niño would correlate very strongly with landslides in San Diego.
But, Abbott said, landslides in San Diego tend to be much smaller and slower moving. They destroy property but usually don't kill people.