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EDITORS: The
100th anniversary of the Great San
Francisco Earthquake is April 18. The
California Geological Survey (CGS) is
regarded as the primary source of
geological and seismological products
and services for decision-making by
California's government agencies, its
businesses and the public. The following
is a short feature about the state
survey. It is the first of several
releases related to California
seismology and CGS’ work we will send in
the weeks prior to the centennial
anniversary.
Attached is a fact sheet with thumbnail
descriptions of CGS’ earthquake-related
programs. More information about those
programs, as well as background that may
be helpful in your coverage of the 1906
earthquake anniversary, is available on
the CGS Web site at: http://www.consrv.ca.gov/CGS/cgs_history/mission.htm.
For more information, or to arrange
interviews with CGS scientists about
earthquake-related stories, please call
(916) 323-1886.
SACRAMENTO -- Olaf
Jenkins experienced the April 18, 1906
Great San Francisco Earthquake as a high
school student in Palo Alto. Many years
later, he recalled the events for
California Geology magazine:
“Since my bed was walking all over my
bedroom and I was sure that the house
would land on its side, I just hung on.
I had been sleeping soundly until just
the very second the great temblor came.
Although it seemed a long time shaking,
it actually lasted only a fraction of a
minute.
“I jumped up to look out my little
window on the third floor of our home on
the Stanford University campus. The view
was of the beautiful sandstone buildings
of Stanford University; but now there
was a great cloud of dust rising. Only
when the dust started to settle could I
make out that not all was there.”
Jenkins, who already was leaning toward
a career in geology at the time, would
go on to become chief of the California
Division of Mines from 1947 to 1958.
The California Division of Mines, which
traces its history almost back to the
Gold Rush, would evolve into the
California Geological Survey (CGS), a
branch of the Department of Conservation
that works with other scientific and
emergency response organizations
throughout the state and around the
world to protect public safety.
“Over the last 125 years or so, our
focus has shifted,” said State Geologist
Dr. John Parrish, one of Jenkins’
successors. “We still do geologic
mapping and locate mineral resources,
but studying and mapping seismic hazards
to ensure that California is better
prepared for the next large earthquake
has become an important facet of our
work.”
In 1851, one year after California was
admitted to the Union, the Legislature
named John B. Trask, a medical
practitioner and member of the
California Academy of Sciences, as
Honorary State Geologist. In 1880, the
California State Mining Bureau was
established, but while the legislature
recognized that geologists could provide
valuable information, the study of
seismic activity was an unknown subject.
In fact, the Bureau’s annual report for
1906 made no mention of the earthquake.
A later report explained:
“After the San Francisco disaster, what
little funds the Bureau had and which
would have been available for field work
had to be used for the purpose of
repairing damages sustained during the
earthquake. The last legislature made no
provision to rehabilitate the Bureau,
although it sustained damage by breakage
of cases and other losses to the extent
of approximately $1,500.”
The Division of Mines (the State Mining
Bureau was renamed several times over
the years) created a geologic branch
with a separate budget in 1929. However,
it wasn’t until the magnitude 7.3
Arvin-Tehachapi earthquake of 1952 that
it began to routinely map and study
earthquakes.
From that humble beginning, a
comprehensive seismic program has been
developed that includes the mapping of
surface fault traces, the development of
landslide and liquefaction zones, the
monitoring of how strong ground motion
effects structures, and review of where
schools and hospitals are located.
“Earthquakes were a fact of life in
California in 1906, as they continue to
be today,” Parrish said. “In terms of
large earthquakes in densely populated
areas, we’ve been fortunate. It has been
relatively quiet since the Northridge
earthquake of 1994. But the scientific
community agrees that the probability of
a damaging earthquake in a population
center in the next 30 years is high.”
The anniversary of the 1906 earthquake,
Parrish added, is an excellent
opportunity to reflect on how far
science has advanced in its
understanding of earthquakes and how
much more there is to learn.
“We cannot predict earthquakes and we
certainly cannot prevent them,” Parrish
said. “All we can do is try our best to
understand them and learn to live with
them by preparing as individuals, as
members of a community, and as
government leaders.”
That challenge was true in 1906, as
well. In the 1980 California Geology
article, Jenkins wrote of walking along
the San Andreas fault after the great
quake, seeing the heavily damaged water
main leading from Crystal Springs
Reservoir to San Francisco, and the need
to prepare for future earthquakes:
“The force that it took to do that
destruction simply amazed us. It was
certain that anything in line of the
moving fault had to give, and that
feature many people found hard to
believe. Very few people at that time
had given a single thought to
earthquakes, and even now it takes a lot
of explaining to get the fact across.”
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