Could we get an earthquake to rival the 9.0-magnitude trembler in Japan? Earthquake engineer Haresh Shah, MS ’60, PhD ’63, professor emeritus at Stanford and head of the university's risk committee before the 1989 Loma Prieta seism, talks about lessons from the past. Excerpts:
Photo by Chuck Painter/Stanford News Service
What level of quake could Stanford withstand?
That's a million dollar question. We believe in the last two decades, Stanford has done an outstanding job with the older buildings as well as all the newer buildings. In a major earthquake—whether on the Hayward Fault or on the San Andreas Fault—Stanford could do reasonably well. In something similar to 1989 earthquake, we'd do just fine. Let's say up to 7 it would do just fine, unless the center of the earthquake is right in our backyard. It has to do with the magnitude of the event and how far away [the epicenter] is.
How should people get ready, just in case?
For people like us, who live really in the earthquake country, we need to prepare ourselves for at least 72 hours of independence from the rest of the world. We have to assume there will be no water, no gas. It may not happen, but potentially it could. So if you are prepared to live 72 hours without anybody helping you, then you can feel assured that you are reasonably well prepared. What that means is you should have drinking water, you should have food, you should have an emergency kit that has a flashlight, radio, some minor injury medical kit. You cannot assume that just because we have done well in the last two decades we'll have no damage. Zero risk does not exist. There's always a risk. What we try to do is minimize that risk. Toward that goal we have done quite well in the last decades.
Is Stanford near any nuclear plants?
The answer is no. We used to have an educational small nuclear reactor in the '40s called the Ryan Lab. But that was decommissioned, and now there are homes there. It was on Stanford Avenue. Today you will see housing for faculty called Ryan Court.
Can we know in advance that an earthquake is about to hit?
We cannot predict earthquakes. We don't know whether it will come while we are talking or whether it will come 10 years from now or 30 years now. The probability of a major earthquake in the next 30 years is extremely high. Looking at the history of events and the amount of stress a given fault can store, we know we are due. The probability of the next 30 years is very high.
Are all Stanford buildings earthquake-proofed now?
There isn’t anything called earthquake-proofed. It's called earthquake resistant. There was a famous engineer,Dr. John A. Blume, ’32, Engr. ’35. He used to say the word “proof” should only be used for whiskey.
What did we learn from the 1989 Bay Area quake?
Our university was in a change mode in terms of what to do with the older buildings and how the new buildings would perform. We had developed a list of buildings that we should worry about, a list of buildings that we should take a second look at, and a list of buildings that we thought would be fine. One of the first buildings that we felt was at risk was the Hoover House, where the president [then Donald Kennedy] lived. We asked him to vacate the home, and he did, and we fixed it. Just after it was completed, the president moved back, and the building was fine [during the quake]. The second example was Roble Hall, where the students lived. We declared that unsafe and [as needing] immediate attention. We closed that hall and asked many students to vacate it and double up in some other buildings that we felt were safe. We fixed Roble Hall, the earthquake came, and it was safe.
So the damage in 1989 could have been much worse?
It could have been terrible because in some of the buildings, there was huge occupancy. It would have been terrible if the earthquake came and the buildings were as they were before. We actually took many, many buildings that were extremely high priority and we started fixing them even before the earthquake. Unfortunately, we could not catch up because of the earthquake. We had damage in Memorial Church, the chemistry building. These were all on our list. [But] a university has to balance limited resources with the risk. We had to take a few buildings at a time. By the time we got to all of them, it would have been 10 years. The damage we got was not [because] we didn't know this would happen but that the earthquake came faster than we expected.
How did you know which buildings were at risk?
We did a detailed assessment. We had a risk committee. We had a huge resource in our structural engineering center, in the Blume Earthquake Engineering Center at Stanford, and in the consulting engineers in town. We had conducted an ongoing university-wide study over a couple of decades. Out of that we would [annually] prioritize which building we had to fix immediately. Even though the age of the building is a good indicator, it’s not the only indicator. We have to look at the structure.
How expensive is it to redo the buildings?
It's expensive. Doing it after [a major earthquake] is more expensive.
Where is the greatest risk in the United States?
The greatest risk today if you ask me is one, in California, and two, in the New Madrid area, which is in the Midwest. Memphis is a big town nearby. It’s at the cross section of Arkansas, Indiana, Illinois and Tennessee. [In 1811 and 1812, huge quakes hit the Missouri town of New Madrid.]
Would it reverberate all the way up to Chicago?
Chicago would see the shaking. You could have shaking all the way from Boston on the east to Denver on the west. In California, we're aware, and our codes are designed in such a way that buildings can resist earthquakes. In the Midwest, because these earthquakes don't occur very often, the older homes are not as well prepared to resist this shaking. They're not ready to do as much as we are. There are thousands of very old buildings, and they would have problems.
What magnitude was the New Madrid quake?
We don't know. There were no instruments in those days. Really scientific instruments are only in the 20th century. [The USGS estimates several of the New Madrid quakes reached a magnitude of 7.7.]
Is your own house earthquake resistant?
Yes. it's quite well designed, so I don't worry about it—wood construction with shear [braced] walls, very tight to the foundation. California homes are wood frame construction. That is by far one of the best. Wood bends and doesn't collapse, whereas bricks or stones just collapse. In general, wood homes, if they're tied to the foundation properly, are quite safe.
What else can we learn from the Japan quake?
It’s a fantastic learning experience for all of us. Today the world is a very complex urban conglomerate. Very few people live in villages. In the old days, we said that when the earthquake comes, most of the damage will come from shaking. In the Japan earthquake, even with magnitude 9, the buildings withstood massive shaking. Most of the damage occurred due to tsunami. Due to tsunami, the nuclear power plants lost their power. They could not cool their nuclear reactors. We did not do a good job in understanding this connected event. Even in the most advanced earthquake country of the world, which is Japan, look at the death and destruction because of the connection between the shaking and the consequences—in this case the tsunami.
What about a tsunami here?
We have the tsunami potential from Mexcio to Canada but not at Stanford [According to Shah, Stanford is too far inland]. There are at least two nuclear plants in California. One is south of Los Angeles, and one is north of Los Angeles. We have an example of what could happen.
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