Tag Archives: Cascadia Subduction Zone

Creating Risk Evangelists Through Risk Education

A recent New Yorker article caused quite a bit of discussion around risk, bringing wider attention to the Cascadia Subduction Zone off the northwestern coast of North America. The region is at risk of experiencing a M9.0+ earthquake and subsequent tsunami, yet mitigation efforts such as a fundraising proposal to relocate a K-12 school currently in the tsunami-inundation zone to a safer location, have failed to pass. A City Lab article explored reasons why people do not act, even when faced with the knowledge of possible natural disasters.

Photo credit: debaird

Could part of solution lie in risk education, better preparing future generations to assess, make decisions, and act when presented with risks that while they are low probability are also catastrophic?

The idea of risk is among the most powerful and influential in history. Risk liberated people from seeing every bad thing that happened as ordained by fate. At the same time risk was not simply random. The idea of risk opened up the concept of the limited company, encouraged the “try once and try again” mentality whether you are an inventor or an artist, and taught us how to manage a safety culture.

But how should we educate future generations to become well-versed in this most powerful and radical idea? Risk education can provide a foundation to enable everyone to function in the modern world. It also creates educational pathways for employment in one of the many activities that have risk at their core—whether drilling for oil, managing a railway, being an actuary, or designing risk software models.

A model for risk education

  • Risk education should start young, between the ages of 8 and 10 years old. Young children are deeply curious and ready to learn about the difference between a hazard and risk. Why wear a seatbelt? Children also learn about risk through board games, when good and bad outcomes become amplified, but are nonetheless determined by the throw of a die.
  • Official risk certifications could be incorporated into schooling during the teenage years—such as a GCSE qualification in risk, for example, in the United Kingdom. Currently the topic is scattered across subjects, around injury in physical education, around simple probabilities in mathematics, about natural hazards in geography. However, the 16 year old could be taught how to fit these perspectives together. How to calculate how much the casino expects to win and the punter expects to lose, on average. Imagine learning about the start of the First World War from the different risk perspectives of the belligerents or examining how people who climb Everest view the statistics of past mortality?
  • At a higher education level, a degree in risk management should cover mathematics and statistics as well as the collection and analysis of data by which to diagnose risk—including modules covering risk in medicine, engineering, finance and insurance, health and safety—in addition to environmental and disaster risk. Such a course could include learning how to develop a risk model, how to set up experiments to measure risk outcomes, how to best display risk information, and how to sample product quality in a production line. Imagine having to explain what makes for resilience or writing a dissertation on the 2007-2008 financial crisis in terms of actions that increased risk.

Why do we need improved risk education?

We need to become more risk literate in society. Not only because there are an increasing numbers of jobs in risk and risk management, for which we need candidates with a broad and scientific perspective, but because so much of the modern world can only be understood from a risk perspective.

Take the famous trial of the seismology experts in L’Aquila, Italy, who were found guilty of manslaughter, for what they said and did not say a few days before the destructive earthquake in their city in 2009. This was, in effect, a judgment on their inability to properly communicate risk.

There had been many minor shocks felt over several days and a committee was convened of scientists and local officials. However, only the local officials spoke at a press conference, saying there was nothing to worry about, and people should go home and open a bottle of wine. And a few days later, following a prominent foreshock, a significant earthquake caused many roofs to collapse and killed more than 300 people.

Had they been more educated in risk, the officials might have instead said, “these earthquakes are worrying; last time there was such a swarm there was a damaging earthquake. We cannot guarantee your safety in the town and you should take suitable precautions or leave.”

Sometimes better risk education can make the difference of life and death.

“San Andreas” – The Scientific Reality

San Andreas—a Hollywood action-adventure film set in California amid not one, but two magnitude 9+ earthquakes in quick succession and the destruction that follows—was released worldwide today. As the movie trailers made clear, this spectacle is meant to be a blockbuster: death-defying heroics, eye-popping explosions, and a sentimental father-daughter relationship. What the movie doesn’t have is a basis in scientific reality.

Are magnitude 9+ earthquakes possible on the San Andreas Fault?

Thanks to the recent publication of the third Uniform California Earthquake Rupture Forecast (UCERF3), which represents the latest model from the Working Group on California Earthquake Probabilities, an answer is readily available: no. The consensus among earth scientists is that the largest magnitude events expected on the San Andreas Fault system are around M8.3, forecast in UCERF3 to occur less frequently than about once every 1 million years. To put this in context, an asteroid with a diameter of 1,000 meters is expected to strike the Earth about once every 440,000 years. Magnitude 9+ earthquakes on the San Andreas are essentially impossible because the crustal fault zone isn’t long or deep enough to accumulate and release such enormous levels of energy.

My colleague Delphine Fitzenz, an earthquake scientist, in her work exploring UCERF3, has found that, ironically, the largest loss-causing event in California isn’t even on the San Andreas Fault, which passes about 50 km east of Los Angeles. Instead, the largest loss-causing event in California is one that spans the Elsinore Fault and runs up one of the blind thrusts, like the Compton or Puente Hills faults, that cuts directly below Los Angeles. But the title Elsinore + Puente Hills doesn’t evoke fear to the same degree as San Andreas.

Will skyscrapers disintegrate and topple over from very strong shaking?

Source: San Andreas Official Trailer 2

Short answer: No.

In a major California earthquake, some older buildings, such as those made of non-ductile reinforced concrete, that weren’t designed to modern building codes and that haven’t been retrofitted might collapse and many buildings (even newer ones) would be significantly damaged. But buildings would not disintegrate and topple over in the dramatic and sensational fashion seen in the movie trailers. California has one of the world’s strictest seismic building codes, with the first version published in the early part of the 20th century following the 1925 Santa Barbara Earthquake. The trailers’ collapse scenes are good examples of what happens when Hollywood drinks too much coffee.

A character played by Paul Giamatti says that people will feel shaking on the East Coast of the U.S. Is this possible?

First off, why is the movie’s scientist played by a goofy Paul Giamatti while the search-and-rescue character is played by the muscle-ridden actor Dwayne “The Rock” Johnson? I know earth scientists. A whole pack of them sit not far from my desk, and I promise you that besides big brains, these people have panache.

As to the question: even if we pretend that a M9+ earthquake were to occur in California, the shaking would not be felt on the East Coast, more than 4000 km away. California’s geologic features are such that they attenuate earthquake shaking over short distances. For example, the 1906 M7.8 San Francisco Earthquake, which ruptured 477 km of the San Andreas Fault, was only felt as far east as central Nevada.

Do earthquakes cause enormous cracks in the earth’s surface? 

Source: San Andreas Official Trailer 2

I think my colleague Emel Seyhan, a geotechnical engineer who specializes in engineering seismology, summed it up well when she described this crater from a trailer as “too long, too wide, and too deep” to be caused by an earthquake on the San Andreas Fault and like nothing she had ever seen in nature. San Andreas is a strike-slip fault; so shearing forces cause slip during an earthquake. One side of the fault grinds horizontally past the other side. But in this photo, the two sides have pulled apart, as if the Earth’s crust were in a tug-of-war and one side had just lost. This type of ground failure, where the cracks open at the surface, has been observed in earthquakes but is shallow and often due to the complexity of the fault system underneath. The magnitude of the ground failure in real instances, while impressive, is much less dramatic and typically less than a few meters wide. Tamer images would not have been so good for ticket sales.

Will a San Andreas earthquake cause a tsunami to strike San Francisco?

Source: San Andreas Official Trailer 2

San Andreas is a strike-slip fault, and the horizontal motion of these fault systems does not produce large tsunami. Instead, most destructive tsunami are generated by offshore subduction zones that displace huge amounts of water as a result of deformation of the sea floor when they rupture. That said, tsunami have been observed along California’s coast, triggered mostly by distant earthquakes and limited to a few meters or less. For example, the 2011 M9 Tohoku, Japan, earthquake was strong enough to generate tsunami waves that caused one death and more than $100 million in damages to 27 harbors statewide.

One of the largest tsunami threats to California’s northern coastline is from the Cascadia Subduction Zone, stretching from Cape Mendocino in northern California to Vancouver Island in British Colombia. In 1700, a massive Cascadia quake likely caused a 50-foot tsunami in parts of northern California, and scientists believe that the fault has produced 19 earthquakes in the 8.7-9.2 magnitude range over the past 10,000 years. Because Cascadia is just offshore California, many residents would have little warning time to evacuate.

I hope San Andreas prompts some viewers in earthquake-prone regions to take steps to prepare themselves, their families, and their communities for disasters. It wouldn’t be the first time that cinema has spurred social action. But any positive impact will likely be tempered because the movie’s producers played so fast and loose with reality. Viewers will figure this out. I wonder how much more powerful the movie would have been had it been based on a more realistic earthquake scenario, like the M7.8 rupture along the southernmost section of the San Andreas Fault developed for the Great Southern California ShakeOut. Were such an earthquake to occur, RMS estimates that it would cause close to 2,000 fatalities and some $150 billion in direct damage, as well as significant disruption due to fault offsets and secondary perils, including fire following, liquefaction, and landslide impacts. Now that’s truly frightening and should motivate Californians to prepare.

Canada earthquake risk 85 years after the Grand Banks earthquake and tsunami

November 18 marked the 85th anniversary of one of the largest and deadliest earthquakes in Canadian history, one that reiterates the importance of managing all drivers of earthquake risk effectively in the region.

The 1929 Grand Banks earthquake and tsunami was a magnitude 7.2 event that occurred just after 5:00 p.m. NST approximately 155 miles south of Newfoundland and was felt as a far away as New York City and Montreal. The earthquake caused limited damage on land and water, including minor landslides, but triggered a significant tsunami that was recorded as far south as South Carolina and as far east as Portugal.

Sea levels near the Newfoundland coast rose between 6 and 21 feet, with higher amounts recorded locally through narrow bays and inlets, and the tsunami claimed 28 lives. Had this event occurred near a more populated region, such British Columbia or Québec, the impacts could have been much worse.

Figure 1: A home in Newfoundland gets dragged out of a nearby cove following the 1929 Grand Banks earthquake and tsunami. Source: Natural Resources Canada

An event like this shows just how complex the Canadian earthquake risk landscape can be and how important it is to keep that view of risk as up-to-date and accurate as possible. On average, Canada experiences approximately 4,000 earthquakes each year. Most are small, but some can be large, particularly along the west coast near Vancouver and Victoria. There, in what is known as the Cascadia Subduction Zone, the Juan de Fuca plate is sliding underneath North America, causing subduction earthquakes, which tend to be less frequent but more severe than other Canadian seismic sources.

RMS has been modeling Canadian earthquake risk since 1991, with the last model update in 2009. The model inherently or explicitly includes the impacts of nearly all drivers of earthquake damage in that part of the world, from ground shaking, landslides, and liquefaction to fire following.

In building, updating, and validating the model over the years, RMS has collaborated with leading Canadian researchers and engineers, including representatives from what is now known as Natural Resources Canada (NRCan). RMS also maintains strong relationships with key insurance organizations and regulatory bodies, such as the Office of Superintendent of Financial Institutions and the Insurance Bureau of Canada, to play a key role in influencing guidelines and practices throughout the Canadian earthquake market.

The next update to the RMS Canada Earthquake Model is targeted for 2016 as part of a larger RMS North America Earthquake Models update. Among other enhancements, the model will incorporate the latest seismic hazard data (2015), internal research by the RMS seismic hazard development team, and introduce a probabilistic earthquake-induced tsunami model that will include losses from inundation along impacted coastlines.

Together, these updates will reflect the latest view of earthquake hazard in Canada, enabling the market to price and underwrite policies more accurately, and manage earthquake portfolio aggregations more effectively.