Seismicity of the Eastern Snake River Plain Region
Idaho: October 1972-October 1983
Timothy E. Doyle
From out of the brush
the pronghorn race our truck
then leap across our path
white sides and legs undulating rapidly
like gazelle in an old safari movie.
We rattle along a washboard trail
near Big Southern Butte, a rhyolite dome
stranded in a chocolate and pale-green sea.
Weathered shield volcanoes lap at its shores
with crumbly scoria crests.
Sage-and-grass scented dust settles at the station,
a solitary antenna mast and solar panel
glinting beetle-blue in the sun.
A geophone lies buried nearby, monitoring
the sporadic sighs of a slumbering crust.
Under the bright spring sky we dryly joke
about the big one coming, pyroclastic flows
to rival Krakatoa by a hundred fold,
exploding from the Yellowstone mantle plume
that sliced a crescent scar across Idaho.
But the lava plain is dormant now, only
minor tremors quake the mountains beyond.
So we check the station, pack our gear
and eat our paper-bagged lunches of peanut butter
or bologna sandwiches in the pure desert air.
On a clear October morning, 1983, the crust
wakes without warning, but not in Yellowstone.
A fault drops six feet at the foot of Borah Peak.
Mag 7.3, it shakes bricks from buildings,
spouts sand from the valley floor, rips roads apart.
The sleeper has shifted and stirred.
For months the earth trembles, murmurs
then slowly quiets,
leaving only pronghorn
to drum the dust.
