Hansen's MagNET » Featured, Science & Technology » Magnitude 7.6 earthquake to hit New York City
Magnitude 7.6 earthquake to hit New York City
Based on data from U.S. Geological Survey (USGS) a magnitude 7.6 earthquake will hit New York, with a 90-100 per cent probability. When exactly the earthquake will strike isn’t known with certainty, but it could happen in the next few weeks.
Using USGS’s Earthquake Probability Mapping, it has been calculated that a magnitude 7.6 (or higher) earthquake is to hit New York once every 4 million years. That is indeed a rare event. However, modern instrumental recordings began just 130 years ago (according to USGS), so although a once-in-4-million-year-event is a rare event, we currently have no way of knowing if the 7.6 magnitude earthquake will hit New York City in 4 days, or in 4 million years, for now. As earthquake expert Ronald Hamburger, senior principal at Simpson Gumpertz & Heger, puts it: “the [once in] 10,000 year earthquake is as likely to occur today or tomorrow, as it is 1,000 years from now.” The same is true for the once-in-4-million-year-earthquake that – according to the map shown below – is expected to hit New York City.
Source: USGS
Ronald Hamburger further explains how stress is relieved in the tectonic plates after a large-magnitude earthquake, which makes it less likely for a large-magnitude earthquake to happen in the same location again. So, if we know when the last magnitude 7.6 hit New York, we could count forward 3-4 million years, until the point in time when an earthquake of the same magnitude is most likely to occur again. But we don’t have data more than 130 years back, so not expecting such an earthquake in the next couple of weeks is unfortunately based on nothing but a misunderstanding of probability.
If someone proposed to build a nuclear power plant somewhere and said the plant would be able to withstand a once-in-100-year-earthquake, people would object. But if people where told the plant would be able to withstand a once-in-10,000-year-earthquake, they would be much easier to convince. However, in reality – although one sounds better than the other – both power plants could be compromised by a large-magnitude earthquake on the first day of operation. So, what sounds better in a black-on-write safety report, doesn’t help us in our colorful everyday life.
In conclusion, people in New York City have good reasons to prepare for a magnitude 7.6 earthquake, and – maybe more importantly – demand city planning that is robust, even to highly unpredictable, but highly consequential, events. Such events are sometimes referred to as Black Swans (a term coined by Nassim Taleb), and even if it seems counter-intuitive to prepare for such rare events, it makes perfect sense, when the veil of ignorance about probabilities is removed from ones eyes.
When it comes to earthquakes, there might be only one way to prevent severe consequences in New York City (and elsewhere), and that is to build cities able to withstand an earthquake similar in strength to the one near Temuco, Chile, on 22 May 1960. This was the strongest earthquake ever registered, at magnitude 9.5, leaving 2 million people homeless. Building cities to withstand a magnitude 9.5 earthquake is a smart solution – not because magnitude 9.5 is the highest ever registered, but because magnitude 9.5 is believed to be the theoretical maximum, as stated by Natural Resources Canada: “Since the tectonic plates have finite dimensions, the magnitude must therefore also reach a maximum. It is believed that the greatest earthquakes can reach magnitude 9.5, which corresponds to the magnitude of the Chilean earthquake.” Only by building to withstand the theoretical maximum can we prevent a catastrophe, like the one currently killing the people of Japan, from happening in New York City – tomorrow or whenever it might hit.
Filed under: Featured, Science & Technology · Tags: Black Swan, dogma, earthquakes, fallibility, forecasting, New York City, nuclear power, postdiction, prediction, probability, risk, robustness, science
Thank you for you comment. Every expert in the field I’ve asked says they cannot predict when. They might be able to tell if there have been an earthquake of such magnitude before, but not necessarily when it happened.
I have to disagree with you on your statement that there’s no way to tell when the last time we had an earthquake of that great magnitude. Obviously with an earthquake, especially one with a magnitude of 7.6 or greater, there would be evidence left behind, even if it were 4 million years ago. Rock formations follow this rule, and you see it all over the world, especially in heavily active areas. Whether it’s a strike slip type (side to side motion) or a thrust (up and down motion), there are scars, faults, or other evidence left, suggesting the seismic activity. Scientists would be able to study the rocks in the surrounding areas, especially the mountainous areas upstate NY and elsewhere, and determine when and if we are in danger any time soon.
Thank you for your thorough comment. However, the argument I give isn’t flawed, although – in retrospect – it could have been explained better. Allow me to (hopefully) do so here.
If we are to believe the USGS, there is a 90-100 per cent probability that a magnitude 7.6 (or higher) earthquake will hit the New York City area once every 4 million years. After one such earthquake, it will be about 4 million years until the next one strikes – give or take a little.
The problem is: we don’t know when the last large-magnitude earthquake hit the New York City area (since we only have data for the last 130 years or so). Maybe the last large-scale earthquake hit the New York City area almost 4 million years ago. If so, we can expect a 7.6 (or higher) earthquake in New York City just about now. And, unfortunately, this might be the case.
But you are right, it might also take another 4 million years before the next earthquake hits New York City – if the previous one hit just before recorded history. That would be great, but there is no way for us to know. And therefore: the numbers presented in a proposal for a nuclear power plant, doesn’t do much for us, except maybe giving us a false sense of safety. As the USGS map shows, there is a 90-100 per cent probability that a magnitude 7.6 or higher will hit. The keyword here is “higher”, indicating that it could be 8.1 or 8.6 – in principle all the way up to the theoretical maximum of 9.5.
In short: Rather than saying the probability is 1 in 40,000 that such an earthquake will hit in the next 100 years, it would be more correct to say: the probability is unknown. We humans have trouble with uncertainly, and – unfortunately – it seems as if we “prefer” (maybe unknowingly) to base our decisions on a flawed forecast, rather than acknowledging that we don’t know.
We would be better off if we learned to make decisions without the need for (misguided) predictions.
The logic behind this article is flawed. The reason people use 100 and 10000 year timeframes for likelihood is because a nuclear plan will be dismantled for economic & efficiency reasons long before operating for 10000 years.
While it is true that the chances of a 7.6 earthquake in New York TODAY are exactly the same as they are on a particular day 4 million years from now, the probability that matters is whether such an event will occur within a specific window — the next 100 years, for the sake of this argument.
There are 36,525 days in the next 100 years. That’s 36,525 chances out of 1,461,000,000 OR 1 in 40,000 (0.0025%).
The odds of a Black Swan earthquake hitting New York while any of the current nuclear plants are operational is far too low to justify the proposed additional design and manufacturing cost. Remember that the corporations that build these things are driven soley by money, and that while the risk (1/40,000) might be enough for an individual to reconsider gambling with his own or a family member’s life, that same individual is unlikely to think twice about the lives of strangers with such a low risk when hundreds of millions of dollars are on the table.
This is not “just a hypothesis”, and I didn’t say it will happen in a couple if weeks, I said it could – and that we have no way of knowing. Thanks for commenting!
This is complete hypothesis and nothing to prove something would happen in couple of weeks. With Japan’s catastrophe in background I guess releasing such articles would only raise panic in the minds. I strongly feel we should refrain from publishing such disturbing data during this time. However I would appreciate if we get to read something optimistic.