earthquake

The Cascadia Earthquake

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A thought-provoking, and frightening, piece by Kathryn Schulz in The New Yorker on the very big earthquake that is likely to strike the Pacific Northwest sometime in the future:

The first sign that the Cascadia earthquake has begun will be a compressional wave, radiating outward from the fault line. Compressional waves are fast-moving, high-frequency waves, audible to dogs and certain other animals but experienced by humans only as a sudden jolt. They are not very harmful, but they are potentially very useful, since they travel fast enough to be detected by sensors thirty to ninety seconds ahead of other seismic waves. That is enough time for earthquake early-warning systems, such as those in use throughout Japan, to automatically perform a variety of lifesaving functions: shutting down railways and power plants, opening elevators and firehouse doors, alerting hospitals to halt surgeries, and triggering alarms so that the general public can take cover. The Pacific Northwest has no early-warning system. When the Cascadia earthquake begins, there will be, instead, a cacophony of barking dogs and a long, suspended, what-was-that moment before the surface waves arrive. Surface waves are slower, lower-frequency waves that move the ground both up and down and side to side: the shaking, starting in earnest.

Soon after that shaking begins, the electrical grid will fail, likely everywhere west of the Cascades and possibly well beyond. If it happens at night, the ensuing catastrophe will unfold in darkness. In theory, those who are at home when it hits should be safest; it is easy and relatively inexpensive to seismically safeguard a private dwelling. But, lulled into nonchalance by their seemingly benign environment, most people in the Pacific Northwest have not done so. That nonchalance will shatter instantly. So will everything made of glass. Anything indoors and unsecured will lurch across the floor or come crashing down: bookshelves, lamps, computers, cannisters of flour in the pantry. Refrigerators will walk out of kitchens, unplugging themselves and toppling over. Water heaters will fall and smash interior gas lines. Houses that are not bolted to their foundations will slide off—or, rather, they will stay put, obeying inertia, while the foundations, together with the rest of the Northwest, jolt westward. Unmoored on the undulating ground, the homes will begin to collapse.

Worth reading in entirety.

Anticipating the World’s Most Expensive Natural Disaster

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Outside of an asteroid hitting a densely populated area, the world’s biggest catastrophe will likely happen in Tokyo, Japan. It’s not a question of if, but when:

Thinking and writing about such matters is unsettling, but we have learned two great lessons from many modern disasters: 1) our response to them is always initially more chaotic and less effective than envisaged in model scenarios; but 2) a higher degree of preparedness can make a substantial difference, both in avoided death and injury and in property damage.

Earthquakes cannot be predicted, but probabilistic appraisals are another matter. Bozkurt et al. used more than 10,000 observations of earthquake intensity accumulated since 1600 to estimate that the probability of severe shaking in Tokyo is 30 to 40 percent during an average 30-year period. In 2006, the Earthquake Research Committee of Japan estimated the probability of an earthquake with the epicenter beneath northern Tokyo Bay at 70 percent in the next 30 years, with the area including Tokyo, Chiba, Saitama, and Kanagawa experiencing shaking of at least magnitude 6, and 25 million people, or 20 percent of Japan’s total population, affected—an event unprecedented in global history.

In the constructed scenario, the earthquake occurs at 6 p.m. on a winter day and damage was calculated for two wind speeds: about 22 km/hour and for a very windy evening with 54 km/hour (the latter average being an unlikely maximum based on the wind speed during the Great Kanto Earthquake of 1923). This was the first time estimates were made for many types of damage a major earthquake would trigger in the world’s largest metropolis. According to this scenario, there would be about 6,400 instant deaths (more than half of them due to fires) and more than 160,000 severely injured people, many of whom would die because they could not be rapidly transported to hospitals, and emergency wards would be taxed far beyond their capacity. Even with the city’s extraordinary advances in earthquake-proof construction, the scenario expects about 462,000 damaged buildings (no tsunami would reach the city in this scenario).

Much larger numbers of people would be affected in many other ways, lasting hours to months. The city that is the global paragon of long-distance urban commuting would see both its highways and railways cut at more than 600 sites and would lose almost a fifth of its electricity supply (all subways and railways are electrified), and hence nearly 4.5 million people would not be able to return home. Even a day later, their number would be still just shy of 4 million. Should the earthquake happen during the coldest part of the year, the city would face a globally unprecedented task of finding emergency shelters for 4 million people who would also be thirsty and hungry.

The most pressing structural challenge would be to restore utilities. At least a third of water supply infrastructure would be damaged, as would close to 20 percent of natural gas flows and more than 20 percent of sewage facilities. The city would face the task of removing about 40 million tons of debris, mostly a jumble of concrete and metals. After 2011’s Tohoku earthquake, the Cabinet Office for Disaster Management revisited these estimates, putting the death toll at 11,000 people, injuries at 210,000, collapsed buildings numbering more than 850,000 (650,000 due to fires), and the total economic loss exceeding ¥112 trillion.

With Japan’s GDP in 2010 being about ¥540 trillion, the damage would be equivalent to at least 20 percent of the country’s annual economic product. As already noted, the country’s GDP (all figures adjusted for inflation) fell by less than 5 percent in 1923, the year of Tokyo’s last great quake, and the war-induced GDP decline was on the order of 50 percent (no value is available for 1945 but in 1946 the economic product was 45 percent below the 1944 level). By any measure, a virtually instant loss of 20 percent of economic product in the world’s third-largest economy would be a disaster of historic, and unprecedented, significance.

We can only do so much to prepare against Mother Nature’s wrath…

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(via Farnam Street)

Readings: Eyjafjallajökull Volcano, Dung and Coffee, Killer Quakes

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Here’s the most interesting stuff I read over the weekend:

(1) “How an Icelandic Volcano Shut Down Europe’s Airspace” [Der Spiegel] – The furious Eyjafjallajökull volcano in Iceland has erupted, and the result is the grounding of thousands of flights across Europe. Since flights are grounded, some people were forced to take more creative ways of getting to their destination:

British comedian John Cleese of Monty Python fame found himself stuck in Oslo. He hired a taxi and was able to reach Brussels for a fee of €3,800 ($5,100).

Der Spiegel does an excellent job of breaking down the story. On a related note, there were a lot of photographs being shared on the web related to the event, but I wanted to create a most representative and compelling set of photos of the Eyjafjallajökull eruption. I posted a gallery on Flickr: Eyjafjallajökull Volcano (worth a look for some incredible images).

(2) “From Dung to Coffee Brew With No Aftertaste” [New York Times] – the most expensive coffee in the world comes from a wild source. A wonderful read!

(3) “Killer Quakes on Rise With Cities on Fault Lines” [Bloomberg] – we’ve had major earthquakes in Haiti, Baja, and most recently, China so far this year. Are we experiencing more earthquakes as of late than usual? A good point by the author:

The difference between a major earthquake and a significant one is whether it occurs near a population center. Seismic events that people feel are newsworthy, those that shake fish or cows are not. Those that collapse cities are especially destructive in lives and rebuilding costs.

But perhaps the most telling line of the piece:

Never before has it been possible to kill 1 million people in a single earthquake, but cities are now big enough to make this possible.