by Anniel 9/25/14
Yes, we had an earthquake this morning at 9:51 Alaska Daylight Time. Our family is still battling some long illness and we were just thinking about getting up when the bed shook. Being earthquake connoisseurs, we decided to remain prone and play the “Earthquake Game,” beloved by many long term residents of Alaska.
“How strong do you think that one was?”
“At least a 5, probably closer to a 5.7 or 5.8, but it lasted a long time.”
“Close to a minute, I’d say. They must have felt it more downtown than we did here. Our ground is more stable. I wonder where the epicenter was? The radio and net are still working, so let’s Google it.”
The quake turned out to be 6.2 on the Richter Scale and was, indeed, close to a minute long. The downtown area did feel it more. Tall buildings swayed, people ran out into the streets, things fell off desks and shelves, but there was no great damage. We didn’t even have a cup fall. The epicenter was just north of Skwentna, an almost nothing place in the long flat area leading to the Alaska Range. Population maybe 20 or so in summer. Our eldest son had worked there one summer while he was home from college, but I had only landed there once on a bush flight. Dirt runway as I recall.
We had not yet met, but both my husband and I were here for the big March 27, 1964 Good Friday Quake. It was the second largest quake ever, and is variously reported at 9.2 or 9.8 on the Richter Scale. Massive damage from that one, and there were 136 lives lost. One of these days we should put that experience in writing, if only to tell of the good, and the few bad things of that day.
As frightening as they are, earthquakes are a natural part of God’s creation and it is important to understand how and why the earth works the way it does.
In the book Rare Earth, Why Complex Life is Uncommon in the Universe, by Peter D. Ward and Donald Brownlee, the authors set forth the conditions for planetary creation and the requisites for life on earth to exist. Chapter 9 is entitled The Surprising Importance of Plate Tectonics. The authors posit that oceans, and an oxygen rich atmosphere with a temperature range that allows liquid water to exist are necessary for any animal life to occur. Linear mountain chains may also be crucial to sustaining animal life on Earth, and such mountain chains are the result of Plate Tectonics. The movement of the planetary crust across the surface of the planet is found on only one planet in our solar system – this Earth where we reside.
The authors hypothesize that:
. . . plate tectonics provides our planet’s thermostat by recycling chemicals crucial to keeping the volume of carbon dioxide in our atmosphere fairly uniform . . . enabling liquid water to remain on the earth’s surface. . . . plate tectonics is the dominant force that causes changes in sea level, which, it turns out, are vital to the formation of minerals that keep the level of global carbon dioxide (and hence global temperature) in check. . . plate tectonics also created the continents.
There are explanations in the book about hot magma becoming basalt loaded with minerals and rocks needing to come to the top of the oceans in order to cool and bring more minerals to the surface, and, when cool enough, to sink and start the whole process over again. One important aspect of this is what are known as Subduction Zones.
Subduction Zones are long, linear regions where oceanic crustal material is driven deep into Earth, not so much by being pushed down as by sinking down by gravity. It is near and parallel to these subduction zones that linear mountain ranges are constructed.
The authors theorize that the constant, slow motion revolving of the Earth’s crust is what causes Earth to be habitable and that means volcanoes near subduction zones, and earthquakes where the Earth’s fault lines collide. In short, plate tectonics mean earthquakes and volcanic activity are necessary for life on earth to occur.
That seems counter intuitive when human beings suffer so grievously from erupting volcanoes and earthquakes.
So, it seems that mankind makes choices about what perils they face, kind of a “choose your poison” scenario. Do you live in a flood zone, a tropical storm zone, a desert, what about tsunamis, tornados, blizzards, wild animals, heat and wild fires? Good grief, just move to Alaska and get almost everything.
Some hunters and fishermen think the trade offs are worth it. • (962 views)