Dennis Mileti, Janice Hutton.https://digitalcommons.usf.edu/nhcc/1010/thumbnail.jp

Hutton, Janice R.

Mileti, Dennis S.

University of Colorado, Boulder -- Natural Hazards Research and Applications Information Center

Scholar Commons - University of South Florida

Initial public response to the Parkfield Earthquake prediction

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University of South Florida
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FMHI Publications Louis de la Parte Florida Mental Health Institute(FMHI)
1-1-1986
Initial public response to the Parkfield Earthquake
prediction
Dennis S. Mileti
Janice R. Hutton
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Scholar Commons Citation
Mileti, Dennis S. and Hutton, Janice R., "Initial public response to the Parkfield Earthquake prediction" (1986). FMHI Publications.
Paper 12.
http://scholarcommons.usf.edu/fmhi_pub/12
HAZARD HOU ECOpy
Natural Hazards Research and Applications Information Center
Campus Box 482
University of Colorado
Boulder, Colorado 80309·0482
INITIAL PUBLIC RESPONSE TO THE PARKFIELD EARTHQUAKE PREDICTION
Denni s Mil eti
Janice Hutton
1986
Quick Response Research Report #16
. he Natural Hazards .
This publication I~ p~rt Of,t formation Center's ongoing
& ApplicatIOns n .Research R rch Report Senes.
. R ponse eseaQUick es I rado.edu/hazards
http://WWW.co 0
Institute of Behavioral Science #6 • (303) 492·6818
ACKNOWLEDGEMENTS
We wish to express our gratitude to the Natural Hazards
Research Applications and Information Center. and particularly to
William Riebsame .and Susan Tubbersing of the Center. for
providing us with the funds needed to perform this
" quick-responsse" research. Neither they nor the Center.
however. are responsible for any of the analyses. findings or
conclusions made in this report.
TABLE OF CONTENTS
ACKNOWLEDGEMENTS ••.
TABLE OF CONTENTS ••
i
ii
A. The Earthquake Prediction. 1
B.
C.
Purpose and Method .•.•.•...•••.•.•••.••
Findings and Conclusions •.•.
1. Earthquake Culture ••
2. Earthquake Ownership.
3. Research as a Prediction ••
1
2
4
6
7
APPENDIX A.
ii
9
INITIAL PUBLIC RESPONSE TO THE 5 APRIL 1985
PARKFIELD EARTHQUAKE PREDICTION
A. The Earthquake Prediction
The 5 April 1985 Parkfield earthquake prediction was a unique
event. Scientists had collected data that led them to conclude that
they could predict the next Parkfield earthquake and speak to the
four elements of an earthquake predi.ction: time, place, magnitude and
probability. The basis for this prediction was presented to the
National Earthquake Prediction Evaluation Council (NEPEC) on November
16, 1984. This council reviews such predictions and evaluates their
scientific merit. Additionally, on February 13, 1985 the California
Earthquake Prediction Evaluation Council (CEPEC) met to evaluate the
prediction. Both councils judged the scientific merits of the
prediction to be sound, and on 5 Apr:i.1 1985 the U.S. Geological
Survey (USGS) issued a public statement predicting the next
earthquake in Parkfield, .California. This prediction (see Appendix
A) constituted a scientifically credible earthquake prediction.
B. Purpose and Method
The purpose of this research was to catalogue initial impacts of
the 5 April 1985 Parkfield earthquake prediction on the members of
the public in-and-around the area of Parkfield. We sought to gather
information on this topic by doing field work and interviews as soon
after the public announcement of the prediction as was possible, but
not so immediately that people would not have had a little time to
think about the prediction. We began our field interviewing
approximately 2 weeks after the prediction was announced.
2Interviews were conducted on a non-randomly chosen set of
Parkfield residents. The official population of Parkfield is 34. We
interviewed 9 adults and 9 school-aged children. The interviews were
qualitative and largely unstructured; however. some structure was
imposed upon the interview format in that five routine questions \~ere
asked in reference to the prediction. These were: (1) what has
changed? (2) what is better? (3) what is worse? (4) what are you
and others doing? and (5) what are you and others not doing?
Additionally. we conducted a review of all local newspapers (The
Daily Press) from 1966--the time of the last characteristic Parkfield
earthquake--through eight months after the 5 April 1985 prediction.
We reviewed these papers for three things: stories about earthquakes
and earthquake-related issues, stories about the 5 April 1985
prediction, and stories about earthquake and earthquake prediction
research.
C. Findings and Conclusions
The findings and conclusions that can be drawn from this work are
tentative because of the limited scope of the data collection
effort. Nevertheless, several insights can be dra\nl from this
research. These findings and conclusions are best viewed as grounded
hypotheses induced from the limited data collected, and each is in
need of more elaborate systematic investigation.
Our general conclusion regarding initial public response to the
Parkfield prediction is that there was virtually no response. The
prediction was issued on 5 April 1985, and it would have largely gone
unnoticed by the residents of Parkfield and its environs had not
national media attention been focused on the event. Locally, the
3prediction was not even newsworthy. The daily Press, the local
newspaper for Northern San Luis Obispo County, for example, did not
run a story on the prediction. On April 16th, 17th and 19th--all
about two weeks after the prediction was issued--the paper covered
earthquake stories concerning Earthquake Preparedness Week, the 1906
San Francisco Earthquake, and an earthquake drill in Los Angeles,
respectively. In May of 1985, the paper ran six earthquake-related
stories (on May 2, 3, 7, 10, 17 and 30th). The 17 May 1985 story
covered earthquake research in Parkfield, and how the quake history
of Parkfield was attracting scientists to do research. June of 1985
also saw stories published about earthquakes, but not in Parkfield.
The point is that the Parkfield prediction, while the target of
national newsmedia attention in April on the heels of the prediction,
was not ne\vsworthy in the local co'mmunity. lYhen a story about the
prediction surfaced in mid-May, some 1 1/2 months after the
prediction was issued, it focused on earthquake research and not the
prediction.
The prediction did not go unnoticed by local residents. Locals
learned of the prediction from the national media. The national
media not only publicized the prediction, they also decended upon
Parkfield to film and interview residents. They found locals, as did
we, altered by the prediction in two ways. First, locals were
talking more about earthquakes in Parkfield than they would have had
the prediction not been issued. However, this was not the result of
the prediction. It was a consequence of having the media in the area
asking questions about the prediction and Parkfield earthquakes.
Second, children in the local school had earthquake issues made part
of their lessons. Again, however, this was more a response to
4national media interviews than the prediction per se; that is,
lessons on earthquakes were above all else an attempt to educate
children so that they might not become scared from the questions
being posed by national reporters.
The significant question regarding initial public response to the
Parkfield prediction, therefore, becomes why was the prediction
virtually ignored. There are four answers to this question provided
by the Parkfield case.
1. Earthquake Culture. An "earthquake culture" exists among the
residents of Parkfield and its environs. It appears that locals have
long ago--and well before the 5 April 1985 prediction--fully
incorporated the earthquake hazard into their local culture, beliefs
and norms. Resulting perceptions and behaviors include not only
recognition and accepta~ce of earthquake risk, but also ideas about
what to do to "successfully" live '-lith earthquake risk and
earthquakes.
Earthquakes are both experienced and anticipated by the residents
of Parkfield; they are expected and defined as much as a part of
living in the areas as is true for any other local characteristic.
The earthquake hazard, and ideas about what to do because of it, are
such a strong component of local culture that the belief system
surrounding the hazard is passed on from generation to generation in
much the same way as other more basic cultural traits transcend and
are shared across generations.
That people in Parkfield and its environs have fully incorporated
the earthquake hazard into their local culture is not a surprize.
Earthquakes occur there often; for example, Richter magnitude
earthquakes of approximately 6 have occurred there in 1881, 1901,
51922, 1934 and 1966. Many local residents recollect the 1966 event,
and many other well-know of prior earthquakes either because they too
were personally experienced, or because others have told them stories
of their experiences with these historical events. It is common folk
knowledge, based on the historical record of the characteristic
Parkfield earthquake, that earthquakes occur every now and then, and
that more should be anticipated in the future. In this way the
residents of Parkfield and its environs have also incorporated
earthquake prediction into their local culture; most presume that
earthquakes will occur in their locale in the future. The historical
track record of earthquake occurrences provide a standing folk
prediction for the future that locals understand and accept.
The earthquake culture in Pa~kfield does more than accept and
anticipate earthquakes. It also clearly defines and limits the risk
posed by Parkfield earthq~akes. Local residents contemplate the risk
of loss in future Parkfield earthquakes on the basis of prior events
experienced and recollected. Relatively recent events--recent in the
sense that their intensity, magnitude and impacts are part of the
collective knowledge shared by residents--have not posed -a serious
threat to life and property. Consequently, locals anticipate that
future earthquake events will be of the same sort. For the most
part, locals have adjusted to accommodate this perceived level of
risk. People have, for example, kept cupboard doors tied shut in
anticipation of a future earthquake and anticipated minimal damage.
People take pride that their homes are able to withstand Parkfield
earthquakes. People are even reassured that it's safer to live
closer to the San Andreas Fault as they do because damage, in tlleir
minds, would likely be higher further away.
uThe Parkfield earthquake culture, therefore, fully recognizes
that earthquakes have and will occur in Parkfield; anticipat~s future
earthquakes on the basis of a standing folk prediction based on the
historical record; limits perceptions of future damage in future
earthquakes based on experiences with Parkfield earthquakes that are
part of the local collective recollection.
Given the Parkfield earthquake culture, it is quite
understandable why the 5 April 1985 prediction went virtually
unnoticed by locals. One of our respondents summed up the local
viewpoint: "When scientists started doing research on earthquakes
around here, that meant scientists finally realized what we always
knew: earthquakes happen here. When that panel of government people
issued their prediction, that just meant that government finally
noticed too." From ~ public viewpoint, the Parkfield prediction was
not one cast in the model of how earthquake prediction is typically
viewed by scientists, sc~olars and government officials; scientists
find something out and tell officials who in turn inform the public;
instead, t~e Parkfield prediction is better cast in the opposite
direction. The public viewed the prediction as "they" finally noticed
what we have always known.
2. Earthquake Ownersh!E. Earthquakes and predicted earthquakes
in the Parkfield area, and likely other places as well, are "mmed."
Parkfield residents were very familiar with their earthquake history,
but they define the recent earthquake in Coalinga as Coalinga's.
Conversely, Coalinga citizens recollect Parkfield's historical
earthquakes as Parkfield's. People in Coalinga and Paso Robles, for
example, when questioned about the Parkfield prediction, viewed the
predicted quake as someone else's problem. This is unfortunate since
the predicted Parkfield earthquake could cause damage in, for
example, Conlingn.
7It appears that the naming and labelling of earthquake
predictions with the names of towns can act as a perceptual
constraint to action by members of the public in other places to
mitigate earthquake loss. Predictions labelled with the name of one
town may actually constrain preparedness and mitigation in other
towns because to so name a prediction "1abels ll the impending quake as
someone else's problem. Initial public response to the Parkfield
prediction in neighboring Coalinga and Paso Robles suggests that an
alternative scheme for labeling earthquake predictions could do much
to increase action by the public-at-Iarge to-prepare for and mitigate
losses from predicted earthquakes.
3. Research as a Prediction. The Parkfield prediction is one
earthquake-related event in a long history of such events in that
area. Stories and explanations provided by lnany respondents suggest
another reason why the prediction went virtually unnoticed by local
residents. The field investigations and research carried out by
scientists in the area, which provided the scientific basis for the
prediction, was more the actual prediction for residents than was the
prediction itself. In fact a large amount of ne,vspapcr coverage ,vas
devoted to the emerging science of earthquake prediction and
prediction research long before the 5 April 1985 prediction. This
coverage described at-length the scientific research being conducted
to predict the next Parkfield earthquake.
Public definition of earthquake predictions may not be equal to
scientific and government definition of earthquake predictions, e.g.,
time, place, magnitude and probability. In Parkfield, the act of
stepping up highly visible earthquake prediction research was itself
perceived as an earthquake prediction. If this phenomenon is
generic, it mayor may not have consequences in a community depending
on the amount of earthquake culture in-place, and local perception of
risk from the impending quake which was low in Parkfield. The
Parkfield case, therefore, perhaps suggests a useful way to vie\~
predictions in other areas is to use the net of prediction research
to help locals gradunlly become used to the idea that an enrthquake
may occur. Precluding other earthquake predictions from "falling
from the blue" may be a worthwhile model that can he borrowed from
Parkfield and used in other future predictions.
APPENDIX A
For release: April 5, 1985
Hairs Office
United States
Department of the Interior
Geological Survey, Western Region
Menlo Park, California 94025
Edna King (415)·323-8111, Ext. 2953
Donovan Kelly (703)860-7444
STUDIES FORECASTING MODERATE EARTHQUAKE NEAR PARKFIELD, CALIF.,
RECEIVE OFFICIAL ENDORSEMENT
The forecast that an earthquake of magnitude 5.5 to 6 is likely to
occur in the Parkfield, Calif., area within the next several years (1985-
1993) has been reviewed and accepted by state and federal evaluation panels
according to an announcement today (April 5, 1985) by the U.S. Geological
Survey.
A letter summarizing the results of the scientific review of the
Parkfield forecast was sent to Mr. William Medigovich, Director of the
California Office of Emergency Services, by Dr. Dallas Peck, Director of
the U.S. Geological Survey.
Parkfield has been the site of a USGS earthquak~ prediction experiment.
that is using sophisticated distance measuring devices and other monitoring
equipment in an attempt -to determine and monitor signals that might presage
an earthquake.
The research that led to today's statement has been carried out by
William H. Bakun and Allan G. Lindh of the U.S. Geological Survey and
Thomas V. McEvilly of the University of California. Their conclusions are
based on analyses of reports of e~rthquakes in the Parkfield area in 1857,
1881, and 1901 and seismograph records of events near Parkfield in 1922,
1935, and 1966. The average interval between these events is 22 years and
statistical analyses indicate a high_.p.robability (over 90 percent) of
another earthquake in the region~within-tJi-e---198,:-1993 intervar:--The
seismograph records of the last three Parkfield earthquakes are very
similar, leading to the hypothesis of a characteristic earthquake in the
Parkfield region of about magnitude 6 on the Richter Scale.
Parkfield lies along the San Andr~as fault in a sparsely populated
region about 170 miles south of San Francisco and 180 ~~les north of Los
Angeles. An earthquake of magnitude 6 is of moderate size, at the
threshold of being able to cause modest damage to some structures that have
not been designed for earthquake resistance.
(more)
(EARTH SCIENCE IN THE PUBLIC SERVICEI
2The last characteristic Parkfield earthquake occurred on June 28, 1966,
registered a magnitude slightly less than 6, and caused only minor damage to
wood-frame houses in the region.
The results of the Parkfield studies by Bakun, Lindh, an~ McEvilly have
recently been reviewed and endorsed by the National Earthquake Prediction
Evaluation Council and the California Earthquake Prediction Evaluation
Council. These bodies advise federal and state officials respectively on
the validity of statements and studies regarding the occurrence of future
earthquakes. The national council concluded that the findings at Parkfield
constitute a long-term prediction, a term adopted by both councils to
describe a statement on the occurrence of an earthquake at a specific place
and within a time interval of a few years to a few decades.
In their evaluation of the research, the two prediction review panels
said that the potential exists for the next earthquake in the Parkfield
region to be larger than the 1966 shock, and for the fault rupture to extend
southeast into the adjacent 25-mile segment of the San Andreas fault. Both
panels agreed, however, that the evidence for this larger earthquake was
speculative and required additional data and.review.
Under a program of earthquake prediction research, the U.S. Geological
Survey maintains an array of sensitive geophysical monitoring instruments in
the Parkfield region in an attempt to predict the occurrence of the expected
earthquake more precisely. The California Division of Mines and Geology
also maintains a large number of instruments to measure the effects of the
earthqyake.
'The California Office of Emergency Serxice~ has reviewed the evaluation
with local officials and will take coordinated action should the extensive
monitoring equipment arrayed throughout the Parkfield region indicate that
the anticipated earthquake is imminent.
~ * * USGS * * *


English

The purpose of this research was to catalogue initial impacts of the 5 April 1985 Parkfield earthquake prediction on the members of the public in-and-around the area of Parkfield.https://digitalcommons.usf.edu/nhcc/1010/thumbnail.jp

Report, Initial Public Response to the Parkfield Earthquake Prediction, 1986

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Initial public response to the Parkfield Earthquake prediction

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