While the disaster in Japan impacted the Pacific Coast of the US, here in Oregon a few million dollars damage at Depot Bay and Brookings, it was mostly a reminder that a subduction zone like the one responsible for earthquake and tsunami in Japan can be found 75 miles of the Oregon Coast.
An earthquake of similar magnitude occurred along that zone on January 26th, 1700. We also know that such events occur every 250 to 500 years. Yes, it’s been 300 years since the last one. We know the earthquake occurred about 300 years ago because the impact of the tsunami is still visible and can be carbon dated. We know that it occurred on January 26th because a large tsunami was recorded in Japan on January 27th.
Large earthquakes are not the only evidence of the subduction zone – so are the Cascade Volcanoes including the beautiful and inviting Mt Hood:
And the angry and threatening Mt St. Helens:
Of course we know all of the Cascade volcanoes have the potential to become angry. Even Mt Hood had just erupted when Lewis and Clarke travelled down Columbia River Gorge.
But it’s the earthquakes and tsunamis that result in large scale regional damage as we have seen in Chile and last week in Japan. It’s not a matter of if it will happen but when – it has happened four times in the last thousand years. It won’t be anything like Japan. The Oregon Coast is relatively sparsely populated with no major economic centers and over much of the coast the elevation increases rapidly. Most of the population lives in the Portland area which will be more than 100 miles from the epicenter and while major damage and destruction can be expected it should fare about as well as Tokyo.
So we wait!