During last week’s rip roarin’ storms and high waves, a lot of sand was washed seaward from the beaches along the Central and North Coasts. Resident Joseph Belzer had his camera with him when the beach erosion, coupled with a low tide revealed many, many tree stumps that was part of the last Cascadia Subduction Zone Earthquake that pounded this region back on January 26, 1700. We know that was the date because when the massive tsunami created by the quake reached Japan, it still had the power to wipe out many low lying fishing villages. It’s in their history books. They called it the “Orphan Tsunami,” orphan because there was no preceding earthquake felt in Japan. It was the tsunami that traveled the entire Pacific and hammered the east coast of Japan on that winter day in 1700.
Geologists and seismic experts have gathered a huge amount of data on ocean floor sedimentation from Vancouver Island to Northern California. And in the sediment layers of mud and rock, geologists like Chris Goldfinger of OSU were able to record every Cascadia Subduction Earthquake going back 10,000 years. Goldfinger, in association with the National Oceanographic and Atmospheric Administration, retrieved those core samples and figured out that these large earthquakes happen at fairly predictable intervals – something like 250 to 350 years. Since the last earthquake in 1700, Goldfinger describes our time period as ripe for another one.
Goldfinger describes the process of periodic uplifts along the Pacific Coast caused by the Pacific Plate undercutting the North American Plate. During these tectonic events, the west coast rises fractionally every year to a point where the plates jam up. No movement. They’re stuck. An irresistible force against an immovable object. But the pressure continues to push the coast upward until suddenly, the interface of the two plates slip. The Pacific Plate dives underneath the North American Plate and the coastline literally falls 10 to 15 feet below where it was before. Those trees in the photos above were killed when their forest was suddenly submerged in sea water.
Surviving the next “big one” requires preparation, of course – food, water, basic medical supplies and citizens band hand-held radios (with a pile of batteries) to talk to the outside world. You’ll also need a house that’s high enough so it’s above the tsunami zone and that it can withstand a 9.5 richter quake. Most houses won’t survive such a horrific shaking of the ground – six feet one way, then six feet the other, back and forth for up to five minutes. The only kind of housing that can survive such an attack is steel constructed homes that don’t buckle like a house built of wood. You may have heard about shipping container homes. They’ve come a long way in the past five years and they’re well worth looking in to.
Our thanks to Joseph Belzer for sharing his photos with us, reminding everyone that being prepared for the “big one” will very likely save your life and make it possible for you to survive long enough until help arrives by air and by sea.