Earthquakes may be impossible to predict due to their complexity

Thursday, 4/24/97 Earthquakes may be impossible to predict due
to their complexity

By Kathryn Combs Daily Bruin Contributor "Journalists and the
general public rush to any suggestion of earthquake prediction like
hogs toward a full trough … (Prediction) provides a happy hunting
ground for amateurs, cranks and outright publicity-seeking fakers."
– Charles Richter, developer of the Richter scale. Since the ’70s,
the problem of predicting earthquakes has plagued the lives of many
across the world. As a result, an aggressive research effort was
mounted to determine how to predict the coming of an earthquake.
Today, after nearly 30 years of intense research, scientists have
not yet found a reliable way to predict when and where an
earthquake will occur and how severe it will be. In a recent
article published in Science magazine, David Jackson, a professor
of geophysics at UCLA, concludes that earthquake prediction may not
be possible. In collaboration with institutions such as Tokyo
University and University of Bologna, in Italy, Jackson concludes
that while the public may hope that earthquake prediction is
possible, it may not be feasible because of the complexity of
earthquakes. "I think that we can make meaningful statements about
probability," said Jackson. But the prediction of earthquakes –
when, where and how severe a quake will be – is a very different
matter," he said. "There are some circumstances when we know that
the probability (of an earthquake occurring) is much higher than
average," he said. "Unfortunately, no matter how you look at it,
those probabilities are still low. From the public’s point of view,
that’s still not earthquake prediction," Jackson added. In the
article, Jackson and his colleagues define the common notion of
earthquake prediction as the "specification of the time, location,
and magnitude of a future earthquake within stated limits."
According to Jackson, there are two main problems with predicting
earthquakes. "You need two things (in order to predict an
earthquake)," said Jackson. "You need a model or statement, and
then you have to test it on several earthquakes," said Jackson, who
is also science director for the Southern California Earthquake
Center. He further explains that because earthquakes are quite a
rare occurrence, it is difficult to test any existing models. "To
develop a model, it is difficult because there are so many factors
to consider. In order to test this model, it is difficult because
we have to wait so long for an earthquake to occur where we are
measuring," said Jackson. Paul Davis, also a UCLA professor of
geophysics, largely agrees with what Jackson has to say and further
explains the many complex events that precede an earthquake.
"Recently, physicists have looked … at whole regions of stress,"
said Davis. "What happens (during an earthquake) depends on a
cascade of events" under the earth’s surface, he said. "The analogy
is a sand pile on a table that you tilt," he continued. "Sometimes
little avalanches of sand will fall and sometimes a whole chunk
will go," Davis said. "(However,) this analogy requires you to know
what every grain is doing, how it is interacting with the next
grain, and how the various adhesions and cohesions work," Davis
said. According to Jackson, factors that scientists have considered
when predicting earthquakes range anywhere from fluctuations in the
gravity field to the behavior of animals prior to an earthquake to
changes in water pressure. However, regardless of whether or not
scientists can predict earthquakes, there is still a lot that
scientists can do in terms of preventive measures. "Earthquake
prediction would be dramatic and would be a lot of fun if we could
do it," said Jackson. "But really the most important thing that
earth scientists can do is to tell where earthquakes will occur and
what the chances are over the long term, rather than the short
term," said Jackson. "Earth scientists are much better at
predicting what an earthquake will do, rather than when it will
occur," agreed Davis. Professor of geophysics John Vidale who has
taught an undergraduate course in earthquakes at UCLA, said that
although he agrees with Jackson, scientists should not give up
hope. "We’ve been working on the subject for a long time and it is
clear so far that we don’t know how to predict earthquakes," said
Vidale. "(However), one thing that we can do fairly well is say how
dangerous a fault will be in the next 20 years. We just don’t know
what to look for and we’ve been looking for 30 years," added
Vidale. JANA BONDERMAN David Jackson does not believe earthquakes
can be predicted. Earthquake Warning Research