Stephani Stephenson on sun 17 oct 99
I also "felt the earth mo-o-o-ve... under my bed" last night. First
earthquake experience for me too. what a strange feeling. When I went
back to sleep I was dreaming about making a slab sculpture and couldn't
help but connect the behavior of slabs in a piece to the BIG 'slabs' or
tectonic plates on which we live.
Ah yes, It reminds of a story about seismology and clay.This was many
years ago. (note: I'm not a geologist , don't even have a masters degree
in SCIENCE.)
Years ago I worked as a ranger and caretaker at a place called Painted
Hills , part of the John Day Fossil Beds National Monument in Central
Oregon. The region fascinating , known for fossils and dramatic
geological formations from many, many different eras. The fossils at
Painted Hills are from the Miocene, 35 million years ago, but there are
much older outcroppings, 200 million years, and many more recent
examples of earth's upheaval .
The Hills themselves are beautiful . Iron striated, colorful soft hills
of montmorillite.You can see them expand when they are wet, seriously.
Nothing grows in them but one rare flower which blooms in the spring.
They were formed when volcanic ash was deposited in the then lakebed.
The ash then metamorphized over time into montmorillite.
One day three seismologists came to the park. They were studying 'earth
tides'. Told me that the earth has imperceptible but measurable'moon'
tides much like the sea.They came to install an extremely sensitive
seismometer in an outcropping of very ancient rock, evidently the
deepest exposed layer of the earths mantle which they could find.
They had to place the seismometer a couple of hundred miles inland or
the influence of the Pacific ocean hitting the Oregon coast would
diusrupt the reading.
I asked what would happen if they put the seismometer in the clay hills
themselves. Their eyes flew open,"Are you KIDDING!?, if we did that a
truck rolling down the highway five miles away would max this thing out.
These hills are like a big bowlful of jelly"
The concept fascinated me . Especially how different rock outcroppings
are more 'rooted' and also have a different 'timbre'. M.C. Richards said
that the German word for clay comes from the word 'ton'
which means 'tone' which has to do with sound and vibration.
We are fortunate here in San Diego that the 'tone' of the quake was
gentle. No pots off shelves, no kiln shift, no one hurt.I know our
desert neighbors felt it more sharply.
Stephani Stephenson
Leucadia, CA
arcilla@inetworld.net
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