Seismology
Predictable publicity
W
that the Earth telegraphs its
hen people at a party
punches, i.e. that large earthfind out I’m a seismolquakes are preceded by observogist, their first quesable and identifiable precursors,
tion is usually “when will the
like many such “obvious” ideas,
next earthquake occur?” This
isn’t backed up by the facts.
suggests (i) that most people are
The popular idea of an “earthfascinated and frightened by
quake prediction” is a warning of
earthquakes, and (ii) they think
an imminent damaging earthseismologists can predict them.
quake, given with sufficient accuUnsuccessful earthquake preracy and reliability to permit closdiction research has been going
ing schools, factories and busion for over 100 years, as has critnesses, mobilizing civil defence
icism of that research. A paper by
forces, enforcing full or partial
de Montalk (1934) has the marevacuation etc. The costs of such
vellously descriptive title “Earthmeasures would be enormous, so
quakes: The futility of predicting
extremely high reliability and
them”. The criticisms by Macelaccuracy would be required.
wane (1946) apply equally today:
Pulling some numbers out of a
“Is it possible, in the present state
hat, let’s say we would need a
of scientific knowledge, to predict Artist’s rendition of P Varotsos. From the title page of “Earthquakes can
50% chance of being right, and
earthquakes...? All reputable seis- be predicted!” (from the comic book Shonen Sunday, 28 June 1995).
accuracy of one day in time,
mologists agree that we have no
about 50 km in space, and 0.5 in magnitude.
meeting, “Assessment of schemes for earthmeans at the present time of arriving at a reli(Magnitude is a logarithmic scale related to
quake prediction”, the clear consensus was
able forecast of any earthquake anywhere.
the energy of earthquakes: unlike stellar magthat individual earthquakes are inherently
The problem of earthquake forecasting has
nitudes, the higher the number, the bigger the
unpredictable because of the chaotic, highly
been under intensive investigation in Califorquake. Roughly speaking, as the magnitude
nonlinear, nature of the source process. The
nia and elsewhere for some 40 years; and we
goes up by 1 the energy goes up by a factor of
Earth appears to be in a state of “self orgaseem to be no nearer a solution of the problem
about 30, but the statistical frequency of
nized criticality” – always teetering on the
than we were in the beginning. In fact the outoccurrence – for a given region – goes down
edge of instability. Exactly when and where
look is much less hopeful.” Richter (1977)
by a factor of 10.) While there’s room for disearthquakes occur, and how large they will
commented: “Since my first attachment to
agreement, something of this order is required
grow after they start, depend on a myriad of
seismology, I have had a horror of predictions
before prediction would pay off. But there are
fine and unmeasurable details of the physical
and of predictors. Journalists and the general
no good prospects for prediction at all at prestate of the Earth over a large volume, not just
public rush to any suggestion of earthquake
sent, let alone with this accuracy or reliability.
in the immediate vicinity of the fault. The idea
prediction like hogs towards a full trough...
Even if the prediction of indi[Prediction] provides a happy
vidual large earthquakes were a
hunting ground for amateurs,
eismologists at the
can be or have been
goal that could be realized, it
cranks, and outright publicityRAS/JAG Meeting on
predicted, without putting
would still be of questionable
seeking fakers. The vapourings of
utility. People would be far better
such people are from time to time
Earthquake Prediction in
such claims in the context
off living and working in buildseized upon by the news media,
November last year came to of the relevant research.
ings that were designed to withwho then encroach on the time of
the broad consensus that
But people living in areas
stand earthquakes when they did
men who are occupied in serious
earthquakes are inherently
prone to quakes want foreoccur. The design of earthquakeresearch.” Developments in the
resistant structures is primarily a
last 20 years do not require any
unpredictable, in any precise casts. How can these two
job for civil engineers, but seismodification of the above views.
quantitative fashion.
conflicting ideas be reconmologists play an important supThe popular belief that earthYet newspapers and other
ciled? The answer must
porting role by providing inforquakes are predictable is at odds
popular media trumpet any
involve peer review and
mation on the expected seismic
with current research. At the
hazard (e.g. Main 1995; Jackson
recent RAS–JAG (Joint Associasuggestion that quakes
open scientific argument.
et al. 1995) and the expected
tion for Geophysics) discussion
S
16
February/March 1997 Vol 38 Issue 1
Seismology
When is an earthquake prediction not a prediction?
Robert J Geller ponders some problems raised at the joint RAS–JAG Meeting
in London on 7 and 8 November 1996.
levels of strong ground motion
(e.g. Anderson and Yu 1996;
Kawase 1996). There are complex trade-offs here – it is economically impossible to design all
structures to withstand all conceivable earthquakes – but this is
one area where seismologists can
make major contributions to
public safety.
Seismologists can also help to
mitigate the effects of a quake by
quickly determining source parameters (location, depth, origin
time, energy etc) and getting this
information to government leaders and the public as soon as possible after a large quake hits. The
importance of this task, which is
sometimes called “real-time seismology”, is underscored by the
experience of the 1995 Kobe
earthquake. The quake struck at
5.46 a.m. (local time), but due to
poor communication the cabinet
did not appreciate the extent of
the disaster until that afternoon.
Most of the dead were crushed in
collapsed structures; perhaps a
quarter to a third of them could
have been saved if relief had been
mobilized promptly. Another big
contribution to public safety by
seismologists is issuing warnings
of tsunamis (seismic sea waves).
Unfortunately the media do not
consider seismic hazard mitigation to be a sexy topic, while
earthquake prediction claims are
avidly publicized. For example,
the claims of J Zschau of the
Geo-Research Centre in Potsdam,
Germany were announced in a
newspaper story (see box, “Tried
and tested?”). Zschau’s claims
have also been extensively reported in the German popular science
magazines Bild der Wissenschaft
(December 1993) and Geo
(March 1996), but he has not yet
published his work in a major
Vol 38 Issue 1 February/March 1997
Tried and tested?
Zschau’s prediction techniques were announced in the following story
in the 16–22 December 1994 issue of The European newspaper.
Researchers close to
quake warning system
Till Mundzeck, London
German and Turkish scientists believe they are on the
brink of a breakthrough in
forecasting earthquakes. It
could save lives and reduce
the huge cost of damage –
more than $100 billion in the
past 10 years. “On average a
major earthquake happens
every third day,” said Prof.
Jochen Zschau of the GeoResearch Centre in Potsdam,
Germany. “The devastating
effects could be considerably
reduced if the approach of the
quake was predictable.” He
spoke on 14 December as two
earthquakes within an hour
shook ski resorts in the
French Alps.
An earthquake analysis system called Seismolap, developed as a joint venture
between the Germans and
Turkish scientists in northwest Anatolia, could provide
the key.
The scientists noted that
Zschau’s Seismolap system is
not an earthquake prediction
system: it does not forecast the
time, location and magnitude of
an earthquake within narrow
and explicitly stated limits. And
claims of precursory variations
in seismicity are an old story.
Richter (1964) commented as
follows: “Short periods of
exceptional quiet in the area of
an approaching earthquake are
often reported... There is difficulty, and some arbitrariness...
in selecting the area which is to
be included in each individual
study. Working after the occurrence, it will almost always be
possible to select the area to
give the expected result; it has
to be shown that this selection
before major seismic activity
in an earthquake-prone area,
there occurred a pause in the
constant but normally imperceptible micro-earthquakes.
“This pause, or hiatus, may
start years prior to the actual
quake, depending on its magnitude,” Zschau said. “Once
this quiet period passed, we
saw the micro-quakes increasing again and clustering
round the epicentre of the
earthquake.” According to
Zschau this usually happened
a couple of days before the
quake. The hiatus–cluster
combination has shown up in
all the earthquake data from
the eastern Mediterranean
that the scientists have
analysed. So far the results
are retrospective, but the
team is optimistic that, in
conjunction with its new
satellite monitoring programme, Readiness, a viable
warning system will emerge.
has a real tectonic significance.”
Reasenberg (1996) applied the
“Seismolap” algorithm to seismicity in California, with the
following conclusion. “Seismolap appears to be unstable both
in these forecasting tests and in
the behaviour of the underlying
algorithm, whose output is sensitive to the values selected for
the free parameters. Its calculations are often based on very
few earthquakes, adding to its
instability. And a nonlinear filter apparently amplifies these
instabilities. The result is that it
tends to generate a large number of extrema and forecasts,
some of which, apparently by
chance, then become associated
with some large earthquakes.”
refereed
journal
(Georefs
1991–1996). Nevertheless, the
Ministry of Education and
Research of the German government granted him approximately
$2 million in funding (for one
year) for a project on “earthquake prediction research”,
apparently without peer review.
Why did the German government allocate so much money for
Zschau’s unproven and apparently ineffective system, which is in
any case a variation on an old
theme? Two factors seem to
play a part here. First, the responsible officials were apparently
unaware of the long history of
failed research on earthquake
prediction. Second, the potential
pay-off is enticing: a system that
could save large numbers of lives
by predicting damaging quakes.
In recent years public officials
in many nations seem to have
decided that “curiosity-driven
research” is bad and “strategic
research” is good. Zschau’s project shows what is wrong with
this idea: the bureaucrats who
dole out the funds seem to base
their evaluation entirely on the
goals of the project, without realistically assessing the possibility
of achieving them. “Strategic
research”, at least in this cartoonlike form, seems doomed for the
same reasons as the Marxist command economy: government
planners simply lack the knowledge to make sensible decisions.
The stakes get much higher, and
the media gets even more frenzied, when scientists, either soidisant or recognized, issue public
predictions. For example, in May
1980 Brian Brady of the US
Bureau of Mines said that earthquakes with magnitude MW = 9.8
and MW = 8.8 would occur at the
subduction zone off the coast of
17
Seismology
Peru in August 1981 and May 1982 respectively (Kerr 1981a,b; Olson et al. 1989). A
foreshock with MW = 7.5–8 was forecast for
June 1981. When this failed to occur, Brady
retracted his prediction. It had no sound basis,
but much time and effort had to be wasted in
evaluation. The prediction caused substantial
unrest; the head of the Office of Earthquake
Studies of the US Geological Survey travelled
to Lima in June 1981 to assure the Peruvian
people there was no cause for alarm.
An even more spectacular debacle involved
Iben Browning, a business consultant with a
PhD in biology but no background in earth
science. Browning predicted that an earthquake with magnitude between 6.5 and 7.5
would strike New Madrid, Missouri (about
250 km south-east of St Louis) between 1 and
5 December 1990 (Kerr 1990, 1991; Gori
1993; Spence et al. 1993). The prediction had
no scientific basis, but Browning’s promotional efforts generated a flood of publicity and
panic: public schools were even closed on 3
December. Browning profited by selling
explanatory video tapes at $99 a copy. Spence
et al. (1993) reproduce over 100 newspaper
and magazine articles on Browning’s prediction and give a wealth of other information.
Another example comes from P Varotsos of
the University of Athens, Greece, who has
been claiming for 15 years to be able to predict earthquakes on the basis of geo-electrical
data. During this period the details of Varotsos’s claims have varied greatly. In 1981 he
claimed to be able to detect precursory electrical signals a few minutes before every earthquake of M ≥ 2.6 within 80 km of his observatory and before some large events at distances of hundreds of kilometres. He now
claims only to predict larger quakes (roughly
M ≥ 5), one or two months in advance (see
Varotsos et al. 1996, Geller 1996, and Geophysical Research Letters 1996).
Varotsos has been remarkably successful in
attracting funds, supporters and publicity. At
the RAS Meeting, S Stiros reported that for
the past 10 years Varotsos and his colleagues
have obtained, without peer review, about
40% of the funds allocated to the anti-seismic
organization in Greece. Several Japanese scientists have become strong supporters. After
the Kobe earthquake they launched an all-out
publicity campaign claiming that if only
Varotsos’s methods had been used in Japan
the Kobe earthquake could have been predicted, and thousands of lives saved.
Eschewing refereed journals, they carried
out this campaign in newspapers and magazines, on TV, and even in comic books. The
18
figure shows the title page of an 80-page, twopart series “Earthquakes can be predicted!” in
the comic book (manga) called Shonen Sunday. T Nagao, a geophysicist now at Tokai
University, is listed on the title page as an editorial consultant. The comic was prepared
with the full cooperation of Varotsos.
The cumulative effect of these and other specious claims, extensively reported by the
media, has been to give ordinary citizens and
government officials the incorrect impression
that earthquakes can be predicted. This not
only leads to wasting funds on pointless prediction research, it also leads to neglect of
practical precautions that could save lives and
reduce property damage when a quake comes.
The scientific community has buried its head
in the sand when it comes to dealing with pre-
They would also
have to show the
statistical significance of
their results – just like
all other researchers.
diction claims. The basic problem is that most
of these claims – Varotsos’s are a classic example – are stated in such a vague and ambiguous way that objective testing is impossible.
First, we have to waste enormous amounts of
time just sorting out whether or not the “predictions” were “successful”. But this is an
exercise in futility because of the ambiguity of
the “prediction” announcements. And after
that we’re faced with the even more daunting
task of evaluating whether or not the “predictions” have outperformed the null hypothesis.
The predictors outflank the peer review
process by taking their case directly to the
media. If they would instead submit their
results for publication in scientific journals,
the burden of proof would be on them to
show that their predictions were formulated
unambiguously. They would also have to
show the statistical significance of the results
– just like all other researchers. And their
claims would be published in a way that permitted verification by independent workers.
The long and tragic history of earthquake
prediction research exposes a dark side of our
science. Basically, work in this field has consisted of incorrectly attributing significance to
signals at or below the noise level. While there
might have been some isolated instances of
intentional improper scientific conduct, in
general workers in this field have systematically deceived themselves. Noisy data have
been treated as signals, studies using posterior
adjustment of parameters evaluated using statistical tests for hypotheses with a priori fixed
parameters, and alternative hypotheses systematically excluded from consideration. The
situation is like unfortunate examples in other
fields (“pathological science” Langmuir 1989,
“cargo cult science” Feynman 1985).
The peer review process isn’t just an arbitrary social convention – it’s a system that has
been developed over the past 300 years for
sorting out scientific controversies. Prediction
proponents should publish in refereed scientific journals, not newspapers or comic books.
Robert J Geller is at the Department of Earth
and Planetary Physics, Faculty of Science,
Tokyo University (e-mail: [email protected].
u-tokyo.ac.jp). His speciality is numerical modelling of seismic wave propagation and inversion
of seismic waveform data for 3-D earth
structure, published in Geophysical Journal
International and other refereed journals, but he
has not yet published in a comic book.
Abstracts from the meeting have been made
available via the World Wide Web – see the
RAS meetings pages, beneath
“http://www.ras.org.uk/ras”, for full details.
References
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Feynman R P 1985 Surely You’re Joking Mr Feynman
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Geller R J 1996 “VAN: A critical evaluation”
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Singapore, 155–238.
Geophysical Research Letters 1996 “Debate on evaluation of the VAN method” 23(11) 1291–1452.
Gori P 1993 Bull Seism Soc Am 83 963–980.
Jackson D et al. 1995 Bull Seism Soc Am 85 379–439.
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February/March 1997 Vol 38 Issue 1