Prelude to the Big One?

[Travis McGee]

http://seismo.berkeley.edu/blog/seismoblog.php/2015/10/26/prelude-to-the-big-one

Prelude to the Big One?

There was an era in earth science more than thirty years ago, when
earthquake prediction was at the top of the seismological research
scale. After some apparent successes in China and other places,
seismologists thought they were close to being able to tell the world
exactly where and when devastating temblors would occur. Parkfield, a
tiny hamlet in central California northeast of Paso Robles, was the
epicenter of this research. There, where the San Andreas Fault is so
strikingly exposed, dozens of scientists from the US and abroad placed
hundreds of sensors into the ground, hoping to catch the latest
precursor. Unfortunately, after more than a decade of enormous effort in
Parkfield, earthquake prediction proved as elusive as the search for the
Midas' touch to turn everything into gold.

One of the questions seismologists tried to answer was, if earthquake
swarms could be the prelude to a Big One. This hypothesis got some
notoriety in the summer of 1975. Six years before, the construction of
the Oroville Dam north of Sacramento had been finished and this tallest
earthen dam in the US had impounded the Feather River without any
problems. But when suddenly in June 1975 earthquakes started to happen
under the reservoir, authorities became worried. Would the quakes shake
to dam to pieces? However, within a month the swarm had subsided and
people breathed a little easier - until August 1, when a quake of
magnitude 4.7 shook the dam. Bruce Bolt, then the director of the
Berkeley Seismological Laboratory, was asked if there was more to come.
He said it was possible and indeed, a few hours later, a magnitude 5.7
quake happened in the area of the swarm.

Map of San Ramon Swarm
These two illustrations show two cross sections through the hypocentral
area, from North to South (NS) and from East to West (EW). Each dot
represents a swarm quake. They are concentrated in a extremely small
volume of less than 8 cubic miles of the Earth's crust (Graphics: Lian
Xue, UC Santa Cruz)

Not only scientists began to ask whether Bolt's statement was a true
prediction or if the occurence of the strong quake under the dam was an
untimely coincidence. Even though we seismologists have clearly failed
to find any reliable precursor so far, the same question is being asked
again today, as it was after the Oroville incident: Is the current
earthquake swarm under San Ramon and Danville in the East Bay a prelude
to something bigger? Starting with a 0.8 magnitude microquake on October
13, more than 400 temblors have since occured along the Calaveras Fault
under the Crow Canyon Country Club. At least eight of these quakes had
magnitudes greater than 3 and were clearly felt all the way to Concord
in the North and San Jose to the South. As of this writing, the swarm
goes on and on.

To say it very clearly: Earthquake swarms are not at all an indicator
that something bigger is about to come. Too many times such swarms have
happened without culminating in a big, destructive quake. This is
especially true for the I-680 corridor. In May a swarm under Concord
came and went. And since 1970 the northern segment of the Calaveras
Fault in the region of Alamo, Danville and San Ramon has seen at least
four swarms, most recently in 2003. Each lasted for weeks or months, but
so far none was closely followed by a significant quake.

Does that mean we can exclude that a bigger, destructive quake will
happen soon on this section of the Calaveras Fault? No, we can't! This
segment of the fault has not had a significant quake since it last
ruptured in the 1860's. Given the stresses continuously exerted on it by
the movements of the tectonic plates here in the Bay Area, the
likelihood of a quake of magnitude 6.7 or greater under San Ramon and
Alamo in the next 30 years is about eight percent. At first glance this
number seems very low - but it is not zero. Such a quake can happen
today, next week, in thirty years or even later than that. And this is
independent of whether the area is experiencing an earthquake swarm or
not. (hra111)

[avag...@gmail.com]

'Given the stresses continuously exerted on it by

the movements of the tectonic plates here in the Bay Area, the
likelihood of a quake of magnitude 6.7 or greater under San Ramon and

Alamo in the next 30 years is about eight percent'

8% not 9 , 10 or 7% ?

6.7 ?

Given the stresses, I say 6.8.

how are we coming to a conclusion here SR swarms are characterized with the phrase 'stress relieving' seismic activity ?

plates move to a new stop during the swarm grinding. A new stop may or may not produce a more intense singular quake event ?

The new stop always produces a new category of new singular quake intensity.

[avag...@gmail.com]

uh

quantity yields information

information yields quantity

so after reading abt the German Fusion Machine

http://www.sciencealert.com/first-of-its-kind-german-stellarator-could-revolutionise-the-way-we-use-energy

and Carson's scholarship to Yale

we conclude San Ramon IS THE BIG ONE

[avag...@gmail.com]

https://goo.gl/7z2BBg

http://www.oregonlive.com/geek/2015/11/scientists_call_reports_of_imm.html

You know, we are watching the quake increases, predictions on sea quakes in and off shore OR/MSH for months now tying the increase to OK fracking of course and so the current whohahaha from the hot sleet state isn't surprising...

Google ties the state together with a following newsline item on a new footpath to the top overlooking the bubbling caldera. Condescending down to the bottom.

The Green River line is to the SE across the pool.

[avag...@gmail.com]

VVVVVVVVVVVVVVVVVVVV?

USGS map at 11/11/2015 9:49 AM shows an OK quake configuration facing the GNW and current flow up to the border past the volcano line.

OK quake line ups before this and now are prob the precursor to increased activity.

Belaboring the point.

http://goo.gl/BStTbv