Alan Kafka's Blog

The Enigma of Why a Magnitude 5.8 Earthquake Occurred in Virginia

2011-12-27T08:06:00.000-08:00

Holiday parties are a time for me to connect with old friends, meet new friends, and get asked a lot of questions about why the Earth quakes along the East Coast.

This year, fellow party-goers here in New England have been telling me that they felt the earthquake that occurred in Virginia on August 23 – and they want to know why a magnitude 5.8 earthquake occurred there. My inevitably disappointing answer: “Nobody really knows.”

They finally have the attention of a seismologist and get to ask the big question, and all they get is “Nobody really knows”? You call that an answer? Have they been cheated out of a great scientific story? I don’t think so. In fact, I would argue that it’s the mysteries of science that are the great and engaging stories. The stories about what we know are much less exciting to me than the explorations of what we don’t know. This is the realm of wonder, awe, suspense, excitement, and fun that makes science a great endeavor.

Now, I should clarify: It’s not that we don’t know anything about the cause of Eastern US earthquakes.

California, and the West Coast in general, is the place in the US that many people think of as “earthquake country.” Most California earthquakes occur near a major boundary separating two of the Earth's tectonic "plates", the North American plate and the Pacific plate. Nonetheless, earthquakes are well known to occur in plate interiors as well, and those earthquakes are called intraplate earthquakes. Intraplate earthquakes are common occurrences, globally as well as specifically in the Eastern United States.

A commonly espoused explanation for the cause of intraplate earthquakes is that "ancient zones of weakness" are being reactivated by forces currently active in plate interiors. In this model, preexisting faults and/or other geological features formed during ancient geological episodes persist in the intraplate crust, and, by way of analogy with plate boundary seismicity, earthquakes occur when the present-day stress is released along these zones of weakness. While this concept of reactivation of old zones of weakness is commonly assumed to be valid, in reality the identification of individual active geologic features has proven to be quite difficult. Unlike the situation for many plate boundary earthquakes, it is not at all clear whether faults mapped at the Earth's surface in the Eastern United States are the same faults along which the earthquakes are occurring.

The magnitude 5.8 Virginia earthquake occurred in the "Central Virginia Seismic Zone", a zone of seismicity where earthquakes have occurred before. But the specific cause of earthquakes in this seismic zone, including that of the recent magnitude 5.8, remains an enigma.

In 1875, an earthquake in this zone shook bricks from chimneys, broke plaster and windows, and overturned furniture. Based on felt effects and damage from the 1875 earthquake, it has been estimated to have had a magnitude of about 4.8. On December 9, 2003, a magnitude 4.5 earthquake occurred in this region causing minor damage, and over the years other small earthquakes have also occurred in the Central Virginia Seismic Zone.

So it is not surprising to seismologists that an earthquake would occur in Virginia, but why it occurred at that particular location, at that particular time, and why it was a magnitude 5.8 remains a mystery. And this is the kind of mystery that drew me to a life obsessed with the enigma of why earthquakes occur in the Eastern United States, deep in the interior of the North American plate.

Click here for a paper summarizing the Virginia earthquake: Mineral, Virginia, Earthquake Illustrates Seismicity of a Passive-Aggressive Margin, by Emily Wolin, Seth Stein, Frank Pazzaglia, Anne Meltzer, and Alan Kafka, Geophysical Research Letters, in press.

Click here to read more about earthquakes in New England: Why Does the Earth Quake in New England?, by Alan Kafka.

Boston Museum of Science: Podcast About the Mega-Quake in Japan

2011-05-07T21:22:00.000-07:00

Click here to listen to my description of the March 11, 2011 Japan mega-quake and earthquakes in general. Click on image above to enlarge.

(On the Boston Museum of Science website, click on "Open audio", then click on the forward arrow.)

Correction: The ocean floor moved upward by about 10 ft, not "a couple of feet" (as I said in the interview).

Financial Costs of Earthquakes and Wars

2011-04-22T18:03:00.000-07:00

Today I read that the cost of the 2011 Japan megaquake might be as much as $305 billion dollars. I don't usually think in terms of billions of dollars (my salary is somewhat lower than that), and I wanted to get some sense of what that number means in the context of things that cost many billions of dollars.

I compared the potential $305B cost of the Japan earthquake to some other earthquakes, Hurricane Katrina, the Gulf Oil Spill, the wars in Iraq and Afghanistan, and some potential scenario earthquakes that might occur in the future. The comparison with wars is not intended to be a political statement, but I think it does give a good visual picture of the context of what earthquakes and other disasters cost (see figure). (Click on figure for an enlarged version.)

The numbers plotted in the figure show that the 2011 Japan megaquake would (if these estimates are right) be the most costly earthquake by quite a large margin. Big earthquakes that might occur in the future near US cities are shown by the scenario earthquakes, plotted in green. The costs of those potential earthquakes could be comparable to that of the Japan megaquake. The cost of the Gulf Oil Spill is about comparable to that of the Chile earthquake, and the cost of Hurricane Katrina is comparable to that of the Kobe, Japan earthquake of 1995.

Note: These numbers are just order of magnitude estimates, and were not very carefully sourced for this blog. There are probably better numbers available in detailed studies. The idea here was just to create a quick and simple visual picture of the order of magnitude differences in the costs of these events. The websites and references that I used for the numbers shown here are given in this Excel spreadsheet.

Why Didn't the Foreshocks Predict the Great Japan Earthquake?

2011-04-10T21:01:00.000-07:00

In the aftermath of the devastating magnitude 9.0 earthquake in Japan, many people are asking whether we “should have known” that the smaller earthquakes that preceded it were warnings of worse to come. But while it is clear in retrospect that there were foreshocks during the few days preceding the main shock, including a magnitude 7.3 foreshock and two other magnitude 6.0 foreshocks, before the fact there was no way to know that they were indeed foreshocks.

Let me explain.

Some large earthquakes have foreshocks, and some don’t. How to (in advance) distinguish a foreshock from any other earthquake remains an enigma. There are, for example, more than 100 magnitude 6 to 7 earthquakes occurring each year, the vast majority of which are not foreshocks of huge earthquakes like the Japan quake. It would, therefore, not be practical to issue an earthquake prediction and call for evacuation every few days when these inevitable magnitude 6 to 7 earthquakes occur, on the slight chance that they might be foreshocks of a huge quake.

So unfortunately, in spite of the now clearly identified foreshocks of the Japan earthquake, we still had no way of predicting the magnitude 9.0 earthquake. It is, however, very clear that a huge earthquake was inevitable along the coast of Japan, even though nobody knew when that earthquake was going to occur. It might not have occurred for 10 years, 100 years, 1,000 years, or even 10,000 years. It is, of course, wise to prepare for the inevitability of major earthquakes in seismically active regions like Japan, but that doesn’t mean that we are even close to being able to predict when those earthquakes will occur. The sober reality is that there is no reliable, scientifically proven method of predicting where and when the next big earthquake will occur.

As Yogi Berra said, “It's tough to make predictions, especially about the future.”

Is a Large Earthquake Likely to Occur at Indian Point Nuclear Power Plant?

2011-03-21T10:54:00.000-07:00

Alan Kafka
Weston Observatory
Department of Earth and Environmental Sciences
Boston College

In the aftermath of the March 2011 earthquake and tsunami in Japan, there is heightened interest (and fear) regarding the seismic safety of nuclear power plants in the United States. Of particular interest is the Indian Point nuclear power plant in Westchester County just north of New York City, and the question of whether a large earthquake is likely to occur there. Seismologists are expected to provide definitive answers to such questions, but unfortunately life -- and Earth processes -- are not so simple.

A recent report from msnbc.com described how, based on their analysis of the Nuclear Regulatory Commission's assessment of nuclear power plants in the US, one of Indian Point's reactors is No. 1 for risk of damage from an earthquake. Furthermore, a number of other eastern US plants are also higher on the list than nuclear power plants in California. The reason for this surprising result is that California power plants were designed to withstand larger earthquakes than these eastern US plants.

It is important not to minimize the real risk of earthquakes hitting nuclear power plants in the eastern US. It is certainly true that there is a real earthquake hazard in the eastern US, albeit significantly less than the hazard in California. The challenge is that unlike the California situation -- where relatively well-understood plate tectonic processes dominate the hazard and thus large earthquakes are more likely to occur in places we expect -- it is not clear where to expect the next large eastern earthquakes. In spite of advances in our research, there still remains great uncertainty about the fundamental question of where future large earthquakes are (and are not) likely to occur in the eastern US. Any attempt to discern whether or not any particular location is more prone to future large earthquakes than any other location is still fraught with uncertainty. We have a long way to go before we will be able to say (if ever) that a given location on a map of the eastern US is really more prone to future large earthquakes than any other location.

A 2008 study by seismologists at Columbia University’s Lamont-Doherty Earth Observatory argued that Indian Point is located at the intersection of two active seismic zones, and is thus one of the least favorable sites in the New York City area from an earthquake hazard and risk perspective. My own assessment of the situation is that the distribution of epicenters lends itself to many possible conjectures of hypothetical fault zones, all of which are based on circumstantial evidence. None of these hypotheses can be considered as concrete evidence that the Indian Point site is necessarily any more prone to future large earthquakes than many other sites in the New York City area.

It would of course be comforting if seismology could tell us which of these two assessments is right. In my many years of experience of being asked to respond to these types of questions, I am often struck by how uncomfortable people generally are with uncertainty. Many people are so desperate for certainty in an uncertain world that they seem to be more comforted being told “Yes, a tragic earthquake is certain to occur in your town next week” than to be told “We just don’t know.” But, the truth is that we just don't (yet?) have definitive answers to the question of what the level of risk is to nuclear power plants in the eastern US.

California does have a higher earthquake hazard, but eastern US power plants have not been built to withstand earthquakes as well as those in California. Hopefully, over time seismologists will be able to reduce the uncertainty and more accurately assess the balance between these two effects. But for now, this will remain a matter of deciding the level of uncertainty that we are willing to accept in order to provide us with energy for our chosen lifestyle. The tragic earthquake and tsunami in Japan provide a stark reminder that seismic risk assessment is both a science and an art.

Calling the Japan Earthquake "Divine Retribution" is Bad for Science and Bad for Theology

2011-03-16T05:28:00.000-07:00

Alan Kafka
Weston Observatory
Department of Earth and Environmental Sciences
Boston College

After the magnitude 9.0 earthquake in Japan, Tokyo governor Shintaro Ishihara commented that the earthquake was "divine retribution" for Japanese egoism. If this kind of response to a natural disaster was just an isolated incident, there would be no reason for me to be writing about it. Unfortunately, however, I am quite often told some variation of this divine retribution story after a tragic earthquake has occurred. My "favorite" response came after I gave a lecture on the great Sumatra earthquake and tsunami of 2004. According to one woman in the audience, since the mainshock occurred the day after Christmas and the largest aftershock occurred the day after Easter, it's obvious that the reason for this tragedy is that God is punishing us for our sins!

I find this kind of thinking to be very disturbing for two reasons: It diverts attention from what science actually can do to help mitigate the tragic effects of earthquakes, and it is also bad theology.

I would hardly claim to be an authority on matters of the theological realm (for discussion of those types of matters, see Rabbi Kafka's blog), but this one seems theologically simple enough that even I can see the logical flaw: What would be the point of any deity (or natural/spiritual force of the universe) killing thousands of innocent people to punish "us" for our sins or to teach people a lesson about egoism? It is hard for me to imagine a worse view of life than to think that innocent people in Japan were killed to teach them (or "us") the right and moral way to live. I sure hope that is not the way our world works!

There is plenty of thoughtful and fascinating philosophy and theology written on the question of why innocent people suffer from tragedies that have no apparent meaning. As seismologists involved in the study of events that are sometimes very tragic, I think it is valuable for us to ponder such imponderable questions, if only to sensitize us to the tragedy a world away from the fascinating and scientifically interesting seismograms we record. But, simplistic answers to such deep questions don't help anybody.

I guess I should be pleased that Shintaro Ishihara publicly apologized for his outrageous comment, but unfortunately I don’t find his apology to be very comforting. I find that this disturbing kind of naïve understanding of the relationship between science and spirit is all too alive and well in our culture.

I think it is better for us to respond to natural disasters by devoting some energy to increasing our understanding of the causes of earthquakes, improving seismic hazard mapping, building more seismically resistant buildings, and developing better emergency management plans, than to blame the tragedy on some bizarre theological cause. Using science to investigate the causes of earthquakes and to help mitigate their effects is (regardless of any particular theology) positive action that leads to making people safer from the devastating effects of earthquakes.

Reflections on the Powerful Earthquake in Japan

2011-03-12T05:42:00.000-08:00

The tragic earthquake that occurred in Japan on March 11, 2011, once again reminds me of the importance of being sensitive in our roles as seismologists regarding the human tragedy caused by powerful earthquakes. It is always a challenge for seismologists to find the correct balance among conveying scientific information about "interesting" earthquakes, communicating our amazement at the incredible power of natural forces in the Earth, and remembering to be sensitive about the human tragedy caused by large earthquakes. But the scientific study of earthquakes is not just fascinating, it’s also practical. Through scientific research on earthquakes we can take positive action that leads to making people safer from the devastating effects of earthquakes. We can mitigate some of the consequences of earthquakes through increasing our understanding of the causes of earthquakes, improving seismic hazard mapping, building more seismically resistant buildings, and developing better emergency management plans to help the victims when tragic earthquakes do strike.

It is important in our roles as seismologists and educators not to forget that the phenomenon we study, and find to be so fascinating, has such tragic consequences for people. But that fascination with the incredible power of earthquakes also inspires people to study them and to unravel their mysteries so that we can take positive action to minimize their tragic consequences.

Seismologist Records Fans' Frenzy Over Touchdown at Football Game

2011-01-12T06:05:00.000-08:00

John Vidale, a seismologist at the University of Washington recorded the fans responding to a touchdown at a football game. Here's the seismogram -

"Hawks 12th Man Goes Seismic"

and here's the story -

"Seahawks Fans Literally Shook the Earth in their Elation over Saturday's Upset of the New Orleans Saints"

Earthquake Activity in the New York City Area

2011-01-10T12:36:00.000-08:00

Click here to read a Wikipedia article that I wrote on Earthquake Activity in the New York City Area. (Since it's a wiki, others are of course revising and editing it.)

I also made extensive revisions to the Wikipedia article on the Ramapo Fault, a fault zone that has been argued to be the source of earthquakes in the New York City area. As described in the article, some seismologists have argued that the Ramapo fault has the potential to produce a major earthquake, but as can be seen in the figure below, earthquakes are scattered throughout the New York City area, with no particular concentration of activity along the Ramapo fault. Thus, my colleagues and I have argued that neither the Ramapo fault (nor any other known fault in this region) has been demonstrated to be any more active than any other parts of the greater New York City area.

Seismicity in the vicinity of New York City. Data are from the U.S. Geological Survey (Top, USGS) and the National Earthquake Information Center (Bottom, NEIC). In the top figure, closed red circles indicate 1924-2006 epicenters and open black circles indicate locations of the larger earthquakes that occurred in 1737, 1783 and 1884. Green lines indicate the trace of the Ramapo fault.

Living on an Active Planet

2011-01-04T10:05:00.000-08:00

We are periodically startled by the occurrence of a major tragic earthquake, reminding us of how active planet Earth is and of the incredible power of nature. Perhaps equally awe-inspiring, though, is how many earthquakes occur every minute of every day.

Many earthquakes occur in areas of low population density where they do not have major effects on people and therefore do not make headline news, but seismic monitoring reveals the daily seismic shifts of our planet. To appreciate just how seismically active the Earth is, consider the following statistics:

Each year, about one truly huge earthquake (magnitude 8 or greater) occurs somewhere on Earth. About one earthquake at least as big as the devastating 2010 earthquake in Haiti (magnitude 7) occurs each month. And about two to four magnitude 6 or greater earthquakes occur every week.

Including earthquakes that are at least large enough to cause minor to moderate damage if they occurred near areas of high population density (i.e., magnitude 5 and greater): There are about four to six magnitude 5 or greater earthquakes somewhere on Earth every day. About two or three magnitude 4 or greater earthquakes occur every hour, and about one magnitude 3 or greater earthquake occurs every two to three minutes. And including the smallest earthquakes that are generally able to be felt by people (magnitude 2): About four to eight magnitude 2 or greater earthquakes occur every minute.

Think about it: While you were reading this blog, a few earthquakes big enough to be felt occurred somewhere on our very active planet.

The Confluence of Geological and Human Scales of Space and Time

2010-09-01T04:09:00.001-07:00

The confluence of two scales of space and time – geological and human – resulted in three events that dominated the news headlines for much of the past year: the tragic earthquakes in Haiti and Chile, and the Gulf oil spill.

It is difficult – perhaps impossible – for humans to comprehend the vastness of geological scales of space and time. Our life experiences are brief and miniscule relative to the scale of the Earth’s immense and complex systems. These long-term global scale processes are thus often hidden from our direct experience. But even though we don't experience these geological processes directly, they affect our lives.

The Haiti and Chile earthquakes were the result of plate tectonic processes, which occur on a time scale of millions of years. These slow, inexorable, long-term Earth processes can occasionally manifest themselves on a very human time scale when, in a matter of seconds to minutes, plate tectonic forces deep within the Earth are released in a major earthquake.

The Haiti and Chile earthquakes once again reminded us that despite the brevity of our lives relative to the powerful forces of nature, we can nonetheless make a difference in mitigating the tragic effects of those forces. Improved earthquake-resistant construction, for example, made it possible for the huge magnitude 8.8 Chile earthquake to be far less devastating than the much smaller magnitude 7.0 earthquake in Haiti. Chile was fortunate to be better prepared when the huge earthquake struck, with well-developed building codes and emergency response plans, and a long history of studying causes and effects of earthquakes associated with the plate boundary that runs along the Chile coast. The fact that Chile was able to prepare for earthquakes, and thus mitigate their effects, is evidence that we needn’t always be passive victims of nature’s “wrath.” There are things that we can do to minimize the destructive effects of earthquakes on society.

The Gulf oil spill on the other hand, resulted from the drilling of a tiny “hole in the Earth,” miniscule relative to the global scale of the geological processes at work to create fossil fuel resources beneath the Gulf of Mexico. The oil beneath the Gulf of Mexico was formed over millions of years by geological processes involving the burial of organic material in a sedimentary basin. Our probing of the interior of our planet to obtain the oil needed to sustain our fossil fuel-based society has been minuscule compared to the vast scale of global Earth processes, and yet that minuscule probing can have major consequences for us living here on the surface.

The Gulf oil spill disaster was yet another reminder that we are still very far from being able to predict the consequences of our poking and prodding of the Earth. The activities of humans on the scale of just a tiny fraction of the thin skin overlying the Earth’s interior can dramatically influence life on Earth. We need energy to run our society, and at least for now, a large part of that energy comes from fossil fuels. But, in spite of the tiny scales of space and time associated with our exploration for and extraction of fossil fuels, the activities involved in finding and using them have major consequences for the continued vitality of our civilization.

We are living off the resources generated by long-term, global scale geological processes, and we are living on the not-so-solid ground formed by geological processes deep within planet Earth. As historian Will Durant put it, “Civilization exists by geological consent, subject to change without notice.” While this power imbalance is humbling, we also need to remember that there is much more we can and should do to actively protect human lives against the destructive forces of nature.

How Deep was the Gulf Oil Spill Disaster?

2010-08-13T06:17:00.000-07:00

How deep into our planet do you think we are drilling to obtain the oil needed to sustain our fossil fuel-based society?

Click here to see that it's a lot less than it might seem considering the extent of damage caused by the drilling for oil in the Gulf of Mexico.

Earthquakes: Scientifically Fascinating Phenomena with Tragic Consequences for People

2010-01-16T08:17:00.000-08:00

The tragic earthquake that occurred in Haiti on January 12, 2010, once again reminds me of the importance of being sensitive in our roles as seismologists regarding the human tragedy caused by powerful earthquakes. It is always a challenge for seismologists to find the correct balance among conveying scientific information about "interesting" earthquakes, communicating our amazement at the incredible power of natural forces in the Earth, and remembering to be sensitive about the human tragedy caused by large earthquakes. But the scientific study of earthquakes is not just fascinating, it’s also practical. Through scientific research on earthquakes we can take positive action that leads to making people safer from the devastating effects of earthquakes. We can mitigate some of the consequences of earthquakes through increasing our understanding of the causes of earthquakes, improving seismic hazard mapping, building more seismically resistant buildings, and developing better emergency management plans to help the victims when tragic earthquakes do strike.

It is important in our roles as seismologists and educators not to forget that the phenomenon we study, and find to be so fascinating, has such tragic consequences for people. But that fascination with the incredible power of earthquakes also inspires people to study them and to unravel their mysteries so that we can take positive action to minimize their tragic consequences.

Natural Hazards, Environmental Degradation, and the Urbanization of Planet Earth:

2009-11-10T12:20:00.000-08:00

Perspectives on the Ethical Challenges Geoscientists Face in an Uncertain World

Alan L. Kafka, Amy E. Frappier*, and Noah P. Snyder, Department of Geology and Geophysics, Boston College. (Paper submitted to Proceedings of the International Conference on Ethics and Sustainability of the Earth, Boston College, February 26–28, 2009.)

Environmental degradation is no longer an issue that concerns only environmental activists. The concern has become a part of mainstream culture, across the political spectrum. But as if the environment itself isn’t enough for us to worry about, there is another aspect of how human activities are affecting our lives on planet Earth that receives less attention: the interaction among natural hazards, environmental degradation, and urbanization (Figure 1). This is an insidious problem because comprehending it requires thinking about processes occurring on geological time scales interacting with processes occurring on the human time scale, and humans are not typically wired to think in geological time.

Natural disasters are inevitable consequences of life on a dynamic planet. We cannot hold back nature from occasionally unleashing its powerful forces on a vulnerable human population. But human actions that cause environmental degradation, as well as the ever-increasing population and built environment in hazard-prone regions, are worsening the devastation wrought by nature.

Geoscientists can help the public and decision makers to address these issues because they are trained to think differently than the general population: “[Geoscientists] take a long view of time, and they expect low-frequency, high-impact events [and] have internalized the vastness of the age of the Earth and relative brevity of human history” (Kastens, et al., 2009). But they can only help if they transmit that perspective in a manner that gives the public an accurate picture of what we do and don’t know about these hazards.

Click on Figures for larger view.

Click here for PDF file of entire paper.

=========================================================
*Now at Department of Geosciences, Skidmore College, Saratoga Springs, New York

Obfuscation and Unnecessary Mathematical Ado in Science Research

2009-10-03T15:11:00.000-07:00

I am often frustrated reading research papers in geophysics that seem to involve total obfuscation and much mathematical ado about what in the end turns out to be some pretty basic, straightforward research. At times I seriously doubt whether the amount of energy I invest in reading these papers is worth what I learn from reading them.

Recently my colleague, John Ebel, shared with me a Boston Globe article about an economist who confessed that he intentionally made a paper he wrote pointlessly complicated so that it would get accepted for publication. This article provides data to support my suspicion that this insidious phenomenon is widespread across disciplines.

“An Economist's Confession: I Have Sinned Against Clarity”,
by Christopher Shea, http://tinyurl.com/y9kvqpx

Shea writes: “At least David R. Hakes, an economist at Northern Iowa University, has the courage to admit what he did: He purposefully made an article pointlessly complicated, hoping that peacock-tail math and dense prose would impress other academics (or, at least, that other economists would pretend to be impressed, so they wouldn't be tagged as unsophisticated).”

Hakes also admits that in the end, he could no longer understand his own paper, and would not have been able to give a talk on it without assistance. He concludes that “the time and effort necessary to read [his own] paper may exceed the benefits received from reading it.”

How is it that the emperor has been able to go on wearing his new clothes for so long?

How Well Can the "Experts" Predict Earthquakes?

2009-06-23T14:08:00.001-07:00

It has been a curious experience for me to be immersed in research on earthquake prediction while the country is going through a financial crisis. I was intrigued by the following quote from USA TODAY (January 2, 2009), as well as similar quotes that I see nearly every day in the blogosphere:

"Market gurus predict stock rebound but won’t rule out extreme move up – or down."

Now, that's a pretty safe prediction! It's like taking a multiple choice test with the options increase, decrease, or remains the same, and choosing “all of the above.” I think that pretty much captures the state of the art regarding earthquake prediction. Seismologists can predict earthquakes about as well as those market “gurus” can predict the stock market. That is, not well at all.

The perennial promise of successful earthquake prediction captures the imagination of a public hungry for certainty in an uncertain world. Yet, the sober reality is that there is no reliable, scientifically proven method of predicting where and when an earthquake of a given magnitude will occur.

It is understandable that people are forever hopeful that there would be “experts” somewhere who can provide us with some methods for predicting earthquakes and thus avoid human tragedy. Unfortunately, as in the case of financial markets, it's not clear that "experts" are able to predict earthquakes any better than intelligent “lay” people who are given access to seismological data.

While procrastinating on my research/writing about earthquake prediction, I was browsing in my local library and found a fascinating book written by Nassim Taleb, entitled The Black Swan: The Impact of the Highly Improbable. Taleb analyzes uncertainty and problems with prediction from the perspective of his career in various aspects of financial markets.

The notion of a “black swan” is described in Wikipedia as:

“a large-impact, hard-to-predict, and rare event beyond the realm of normal expectations ... The term black swan comes from the assumption that 'All swans are white'. In that context, a black swan was a symbol for something that could not exist. The 18th Century discovery of black swans in Western Australia metamorphosed the term to connote that the perceived impossibility actually came to pass.”

Here is Taleb’s working definition:

“What we call here a Black Swan (and capitalize it) is an event with the following three attributes: First, it is an outlier, as it lies outside the realm of regular expectations, because nothing in the past can convincingly point to its possibility. Second, it carries an extreme impact. Third, in spite of its outlier status, human nature makes us concoct explanations for its occurrence after the fact, making it appear to be explainable and predictable.”

Taleb argues that, because of the possibility of black swans, many (most?) types of phenomena are essentially impossible to predict. He further argues that many so-called experts in a wide variety of fields have developed very sophisticated mathematical models of all sorts of phenomena—but because black swans are hard to incorporate into the models, the models typically don’t account for these high-impact events that actually do occur. Thus, he concludes that experts don't predict any better than “non-experts” are able to predict. In fact, if you compare what actually occurs to what the experts predicted to occur, they typically do at least a little bit worse than non-experts!

According to Taleb:

“... [C]ertain professionals, while believing they are experts, are in fact not. Based on their empirical record, they do not know more about their subject matter than the general population, but they are much better at narrating – or, worse, at smoking with complicated mathematical models.”

Some would say that Taleb takes too extreme a position on these matters. Read the book and decide for yourself; but when it comes to earthquake prediction, I do think that there is more than a grain of truth to his argument.

In 2004, a feature article posted on NASA’s website heralded an earthquake prediction project they funded as an “amazing success” - Earthquake Forecast Program Has Amazing Success Rate.

Being inherently skeptical about these matters, a colleague and I decided to test just how amazing this particular success was (Kafka and Ebel, 2007). We tested the NASA-funded prediction model, known as Pattern Informatics (PI, Rundle et al., 2002*), by comparing it to a much simpler method that I developed, called Cellular Seismology (CS, Kafka, 2002, 2007). At its core, CS assumes nothing more than that future earthquakes will occur near past earthquakes. Thus, testing PI against the CS model is a good way to compare how well an “expert” model performs when compared to what I would argue is essentially a "non-expert" model. I see CS as a non-expert model because I imagine that many non-experts would likely come up with some variation on CS as a “common sense” component of what they think should be included in an earthquake prediction scheme.

Our results: PI doesn't perform any better than CS, and we have yet to find anything in the record of past seismicity that is any more predictive of where future earthquakes are likely to occur than the trivial, intuitive notion that future earthquakes tend to occur near past earthquakes.

We continue to compare other methods to CS, and it will take many more years of observing earthquakes before we will have enough evidence to discern the extent to which other methods might actually outperform CS. But to date, we have yet to find any method that does any better than CS (see for example Kafka and Ebel, 2009). Although we have certainly not conducted an exhaustive analysis of the questions addressed here, the results of our studies do suggest the possibility that Cellular Seismology, simple as it is, may actually be a measure of “all we can know” about the future occurrence of earthquakes. Hard as it may be for the public (and for seismologists themselves) to accept this conclusion, the results of my research suggest that such a possibility needs to be considered.

As Yogi Berra said, “It's tough to make predictions, especially about the future.”

* Rundle, J.B., K.F. Tiampo, W. Klein, and J.S.S. Martins (2002). Self-organization in leaky threshold systems: The influence of near-mean field dynamics and its implications for earthquakes, neurobiology, and forecasting, Proc. Natl. Acad. Sci. U.S.A. 99, 2514-2521, Suppl. 1.

Calling it Bad Karma is Bad Karma

2009-06-22T06:11:00.000-07:00

(Note: This is a revised version of a post that originally appeared on the BC-ESP Discussion Forum blog.)

Shortly after the tragic earthquake in Sichuan, China, actress Sharon Stone commented that the tragic effects of the earthquake were the result of “bad karma” (because of how the Chinese are treating the Tibetans). If this kind of response to a natural disaster was just an isolated incident, there would be no reason for me to be writing about it. Unfortunately, however, I am quite often told some variation of this bad karma story after a tragic earthquake has occurred. My “favorite” response came after I gave a lecture on the great Sumatra earthquake and tsunami of 2004. According to one woman in the audience, since the mainshock occurred the day after Christmas and the largest aftershock occurred the day after Easter, it’s obvious that the reason for this tragedy is that God is punishing us for our sins!

I find this kind of thinking to be very disturbing for three reasons: It is bad theology, it diverts attention from what science actually can do to help mitigate the tragic effects of earthquakes, and it is, in itself, the essence of bad karma.

I would hardly claim to be an authority on matters of the theological realm (for discussion of those types of matters, see Rabbi Kafka's blog), but this one seems theologically simple enough that even I can see the logical flaw: What would be the point of any deity (or natural/spiritual force of the universe) killing thousands of innocent people to punish “us” for our sins? It is hard for me to imagine a worse view of life than to think that innocent children in a school in China were killed to teach the Chinese government the right and moral way to treat the Tibetans. I sure hope that is not the way our world works!

There is plenty of thoughtful and fascinating philosophy and theology written on the question of why innocent people suffer from tragedies that have no apparent meaning. As seismologists involved in the study of events that are sometimes very tragic, I think it is valuable for us to ponder such imponderable questions, if only to sensitize us to the tragedy a world away from the fascinating and scientifically interesting seismograms we record. But, simplistic answers to such deep questions don't help anybody.

I guess I should be pleased that Sharon Stone publicly apologized for her outrageous comment, but unfortunately I don’t find her apology to be very comforting. I find that this disturbing kind of naïve understanding of the relationship between science and spirit is all too alive and well in our culture.

And, why do I say that calling it bad karma is, in itself, bad karma? While I do not believe in a deity who keeps score of our actions and punishes us when our score is too low, I do think that what some people call “the law of karma” is a reasonable way to think about the effects of our actions. Call it what you want, but actions do have consequences. I think it is better for us to respond to natural disasters by devoting some energy to increasing our understanding of the causes of earthquakes, improving seismic hazard mapping, building more seismically resistant buildings, and developing better emergency management plans, than to blame the tragedy on some bizarre theological cause.

Using science to investigate the causes of earthquakes and to help mitigate their effects is “good karma” - it is positive action that leads to making people safer from the devastating effects of earthquakes.

Faults and Earthquakes in the Greater NY City Area

2009-06-19T11:49:00.000-07:00

My thoughts on faults and earthquakes in the New York City area, and how all of that relates to the intersection of Science, the Media, and the Public can be found here.

"The only people who find what they are looking for in life are the fault finders" - Foster's Law

Earthquake Prediction: You Want Answers, We’ve Got Questions

2009-06-04T11:44:00.001-07:00

While driving to give a lecture on earthquake prediction to a large class of non-science majors, I remembered the Radio Shack sales pitch, “You’ve got questions, we’ve got answers.” It seems to me that this quote captures the cultural divide between seismologists and the public regarding earthquake prediction.

Based on my interaction with the public regarding earthquakes (particularly after significant earthquakes occur), and on my experience with courses that I teach at Boston College, I have come to the conclusion that there is a great divide between seismologists and the general public on the topic of earthquake prediction. The public wants answers but what characterizes seismologists (and scientists in general) more than anything else is their intrigue with the process of finding answers to questions, rather than the answers themselves. In the words of Richard Feynman, we are driven by “the joy of finding things out.” Sure seismologists sometimes get egotistical about their latest earthquake prediction-related “discovery”, acting as if they are close to finding some ultimate “answer” about earthquake predictability (and I am certainly at times guilty of that egotism myself). And sure we get cynical as we get older and start to feel that we have lost the “naive” enthusiasm about a life of “exploring the unknown” that we had in graduate school or earlier. But, my experience with seismologists (and other scientists) of all ages is that, if you “scratch the surface just a little bit”, you will find that we are still in our hearts living the ideal that drew us into the world of science in the first place: We love to think about the big unanswered questions, and we love the challenge of trying to figure out the answer.

When non-scientists meet me, they are often thrilled to find a real seismologist who will be able to finally give them answers to earthquake-related questions they have been thinking about all of their lives. After a short while, I can see their disappointment when they find out that they want answers, and I’ve got questions. So much so that I don’t think it is too much of an exaggeration to say that they would rather hear me say, “Yes, there will be a magnitude 8 in your backyard tomorrow morning…” than to hear me say, “Well, that’s actually a big and fascinating question that seismologists don’t know the answer to and are actively investigating…”

Another aspect of this cultural divide: Most scientists I know are convinced, with good reason, that this curiosity driven science is precisely what leads ultimately to real and useful answers in the long run. However, that argument is usually not very compelling to a public that is hungry for immediate results and for certainty in an uncertain world. I think it is precisely the interplay between what is certain and what is uncertain that makes science fun, and that ultimately does yield answers to important questions (although sometimes to different questions than the ones we were originally seeking to answer).

So, where does this leave us? It leaves us with a big mismatch between what the public wants, and what we love to provide. At times I despair that this divide will never be bridged because the public has very little interest in this unending “quest for truth” that draws us into careers as scientists.

I am curious to hear what other seismologists and non-seismologists think about this divide. Do you as a seismologist have this same experience? Do you as a non-seismologist find it frustrating that seismologists are not providing the answers you are seeking?

If you do think that this is an accurate description of the situation, what do you think we can do to make the situation better? Is this a matter of scientists learning how to tell our story in such a way that we more effectively market whatever answers we have (incomplete as they may be)? Is it our obligation as public servants to focus on what we do know and minimize our excitement about the mystery of what we don’t know?

Thoughts, comments (or maybe even some “answers”) on this topic are welcome.

Why Does the Earth Quake in New England?

2009-06-04T10:00:00.000-07:00

Yes, it's true. Earthquakes do occur in New England...

In the evening of October 2, 2006 residents of coastal Maine felt the ground shake from a magnitude 4.2 earthquake located near Bar Harbor. In nearby Acadia National Park, falling rocks forced the closure of the Park Loop Road.
On December 20, 1940, residents of Springfield, MA felt vibrations from an earthquake centered near Ossipee, NH. The Springfield Republican newspaper reported that "dishes toppled from the shelves in many kitchens and wall pictures swung pendulum fashion on their fastenings."
On November 20, 1755, the Boston Weekly News-Letter reported "a most terrible Shock of an Earthquake: The conditions were so extreme as to wreck the Houses in this Town to such a degree that the Tops of many Chimnies, and some of them quite down to the Roofs, were thrown down. . . ." This earthquake was centered off the coast of Cape Ann, MA.