Tuesday, July 6, 2021

PBS examines the risks from a major earthquake in the Pacific Northwest

I foreshadowed today's topic in the footnote to Drought, fire, and mudslides in California, a story I tell my students.
All that is before I lecture about earthquakes, which really freak my students out. I have a video from PBS NOVA to share about that risk, too. Stay tuned.
Without any further ado, I present that video, The Pacific Northwest is due for a Major Earthquake.

An 8.0-magnitude-plus earthquake hasn't rumbled beneath the Pacific Northwest since the 1700s. Now, the region is due for the next "big one" and a subsequent tsunami. Coastal Indigenous communities could be severely affected. (Already, the Shoalwater Bay Tribe is constructing a tsunami tower to give their residents a better shot at survival in the face of this kind of natural disaster.)

Clues from the past—paired with modern-day science—can help us better understand why this area is at risk and how to best mitigate an earthquake and tsunami's effects.
Note the use of "contiguous United States." That excludes Alaska's Good Friday Earthquake of 1964, which had a magnitude of 9.2. That will probably remain the most powerful earthquake to stike the United States as a whole for the foreseeable future. Also, strictly speaking, the area affected by the 1700 earthquake wasn't part of the United States yet or territories of any colonial power, which is why I mention both the New Madrid earthquakes of 1811-1812 and the San Francisco earthquake of 1906 to my students as the largest temblors to strike the Lower 48. Still, I might add this quake to my lecture. If I did, I would more likely show PBS Terra asking Will the Cascadia Earthquake be the Worst Disaster North America’s Ever Seen?

The Cascadia Subduction Zone is a sleeping monster lurking just off the Northwest coast of the United States. It extends 600 miles between Northern California and Vancouver B.C. and experiences a massive megathrust earthquake every 250 years on average. The last one happened 321 years ago and scientists say there is a 30% chance we’ll see another in the next 50 years. It’s expected to rival the 9.0 quake that shook Japan for 6 minutes, which was the most destructive natural disaster in human history. It unleashed a tsunami that reached 100 feet in some areas, caused an estimated $360 billion in damages and claimed some 16,000 lives.

If this sounds ominous, that’s because it is. As catastrophic as the Tohoku quake was, Japan is light years ahead of the United States when it comes to earthquake preparedness. This grim reality has many experts very worried. And in this episode of Weathered we spoke with some of them about what we can expect when the “Big One” does hit, the kinds of work that need to be done to make our communities more resilient, and what you can do to keep yourself and your loved ones safe.
In addition to showing the destruction from the Fukushima earthquake and tsunami for comparison, PBS Terra's video depicts the kind of damage the projected quake would inflict on the Pacific Northwest, which will impress my students. It also explains what can be done to prepare for the quake. Maybe that will scare my students less. Just the same, the prospect of this quake has dissuaded my wife and me from moving to the Pacific Northwest when I retire. So has the area no longer being immune to extreme heat.

I'm not done with natural disasters this week. NOAA predicted another active Atlantic hurricane season with "13 to 20 named storms (winds of 39 mph or higher), of which 6 to 10 could become hurricanes (winds of 74 mph or higher), including 3 to 5 major hurricanes (category 3, 4 or 5; with winds of 111 mph or higher)." So far, that's coming true with the fifth named storm and first hurricane, Elsa, which Accuweather forecasts will make landfall north of Tampa, Florida tomorrow morning before moving up the Atlantic coast of the U.S. and Canada the rest of the week. That will cause a lot of damage and news coverage, which I plan on reporting here. Stay tuned.

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