...

ppt

by user

on
5

views

Report

Comments

Description

Transcript

ppt
ESS 202
Today’s lecture
• Scaling
– Magnitude, rupture area,
duration
– Also energy
• Numbers of quakes
• Earthquake sequences
• Quake Prediction
4 levels of predictability
• Time-independent hazard
• Time-dependent hazard
• Earthquake forecasting
• Deterministic prediction
Time-independent hazard
• Earthquakes are a random process in time
• Estimate future long-term seismic hazard from
– use past locations of earthquakes
– geological recurrence times
– active fault locations, and deformation rates
• Then calculate the likely occurrence of groundshaking
– From source-magnitude probability
– path and site effects,
– include a calculation of the associated errors
• Such calculations can be used in
– building design and planning of land use
– for the estimation of earthquake insurance.
Time-dependent hazard.
• Here we accept a degree of predictability in
the process, in that the seismic hazard varies
with time.
• We might guess that the hazard increases with
passing time after the last previous event.
– 'characteristic earthquake' with a relatively similar
magnitude, location and approximate repeat time
predicted from the geological dating of previous
events.
• Surprisingly, the tendency of earthquakes to
cluster in space and time includes the
possibility of a seismic hazard that actually
decreases with time.
Earthquake forecasting
• Here we predict some of the features of an impending
earthquake, usually on the basis of the observation of a
precursory signal.
• The prediction is still probabilistic.
– The magnitude, time and location are not given precisely or
reliably.
– Forecasting also should include a precise statement of the
probabilities and errors involved.
• The practical utility is to enable the relevant authorities
to prepare for an impending event weeks to months
ahead of time.
• Practical difficulties include
– identifying reliable, unambiguous precursors
– the acceptance of an inherent proportion of missed events
or false alarms, involving evacuation for up to several
months at a time, resulting in a loss of public confidence.
Deterministic prediction
• Earthquakes are inherently predictable.
• We reliably know in advance, so that a
planned evacuation can take place
– their location (latitude, longitude and depth),
– magnitude, and
– time of occurrence.
Probability
• How often you expect something to
happen
– Example - flipping a coin lands on
heads 50% of the time
• Reported as percent (50%), decimal
(0.5) or fraction (1/2)
• Must be between 0% and 100%
What is Probability?
• Relative frequency of a given
outcome when repeating the
game (coin tossing,…)
• We say something like 80%
probability of an M>7 in the next
30 years
• And we can’t repeat the game,
or even check how well it’s
working
Probability of quake
• Find the faults
• Estimate how faults are segmented
• How does each segment behaves
– Size of its quakes
– Time between quakes - recurrence
interval
• Sum up risk from all segments of all
faults
– (This exercise tells how much shaking)
• Then figure out expected damage
Fault zone segmentation
• Characteristic earthquake model
– Only one segment breaks at a time
• Segments defined by
– Ends of fault traces
– Fault intersections?
– Changes in rock type along fault?
• Best guesses - segment defined from
prior quakes.
• Not clear whether the concept of
fault segmentation is accurate or
useful.
Wasatch Fault
segmentation
1
Keller, 8-21
2
3
4
5
6
Trench in Japan
Age of faulting events
on the Wasatch Fault
Provo
History
of
Wasatch
segments
Pinter workbook
10-4
Now (age in years) 6000
Characteristic behavior of
segments
Keller, Table 8-2
Cookie cutter
How does this apply to an
entire seismic region?
• Outline
– Segmentation of the San Andreas Fault
– Behavior of a segment on the San
Andreas
– Probabilities for San Andreas segments
– Locations of all SoCal faults
– Total probability across SoCal
• For level of shaking
• For level of damage
San Andreas
segmentation
Four
major
segments
Keller, 8-20
1906-type
events
creep
1857-type
events
Trenching sites
Pallett Creek: A former marsh
• Very fast deposition
• Offset beds overlain
by continuous beds
• Earthquake occurred
between depositing of
bottom and top beds
• Dated by finding formerly
living matter (plant leaves,
etc.) and using Carbon-14
http://piru.alexandria.ucsb.edu/collections/atwater/saf/slide25.jpg
“Big One”
history
in SoCal
“1857-type”
segment
Keller, 8-23
From this history
• 10 events in 1300 years
– An event every 130 years, on average
– Last event 145 years ago
• They’re overdue!
• But events are not regularly timed
• So another guess would be
– about 25% chance in next 30 years
– (that’s 30 years / 130 year repeat
time)
30-yr probability of quakes in California
Note absence of Northridge, Landers, Hector Mines, ...
1906 repeat
Parkfield
1857 repeat
Yanev
p. 39
1857-type is given 30% chance in 30 years
Example of a Forecast:
2002 Working Group Bay
area report
• Calculated 62%
probability of a
major (≥6.7)
earthquake n the
Bay Area in the
next 30 years
Image courtesy USGS
Predicted
shaking
from
Hayward
fault event
Combine earthquakes
From all
known faults…
…and some
model of
unknown
faults
Shaking
potential
All known big faults in SoCal
SCEC web page
Most faults have longer repeat times than San Andreas
A probability map for SoCal
Number of times
per century that
20% g will be exceeded
SCEC web page
World Hazard
Philippines, 1990
Europe,
Middle East,
and Africa
Turkey, 1999
Americas
Mexico City, 1985
Some problems and
complications
• Are magnitude 8-9 quakes possible on all
faults, or just big faults?
• Do segments always break one at a time,
or sometimes together? (same question,
also a restatement of characteristic
quake idea)
• Is seismicity uniform over time?
• How many faults don’t we see?
• Effect of strong shaking on soil
Hazard and Risk
• Hazard – probability that a given area
will be affected by a given destructive
process
• Risk – Probability that a loss will occur
• Hazard is what seismologists predict
– Includes earthquake probability
• Risk is what insurance companies, the
government, etc. need to know.
• How do we close the gap?
• Risk = hazard * vulnerability * value
FEMA Hazus results
• Average Annual Earthquake Loss by state
WA
WA
WA
WA
WA
WA
ME
ME
ME
ME
ME
ME
MT
MT
MT
MT
MT
MT
ND
ND
ND
ND
ND
ND
MN
MN
MN
MN
MN
MN
OR
OR
OR
OR
OR
OR
SD
SD
SD
SD
SD
SD
ID
ID
ID
ID
ID
ID
WI
WI
WI
WI
WI
WI
CA
CA
CA
CA
CA
CA
UT
UT
UT
UT
UT
UT
PA
PA
PA
PA
PA
PA
IA
IA
IA
IA
IA
IA
NE
NE
NE
NE
NE
NE
NV
NV
NV
NV
NV
NV
IL
IL
IL
IL
IL
IL
CO
CO
CO
CO
CO
CO
NY
NY
NY
NY
NY
NY
MI
MI
MI
MI
MI
MI
WY
WY
WY
WY
WY
WY
KS
KS
KS
KS
KS
KS
OH
OH
OH
OH
OH
OH
IN
IN
IN
IN
IN
IN
MO
MO
MO
MO
MO
MO
VT
VT
VT
VT
VT
VT
NH
NH
NH
MA
MA
MA
CT
CT
CT
CT
CT
CT
NJ
NJ
NJ
NJ
NJ
NJ
DE
DE
DE
DE
DE
DE
DC
DC
DC
DC
DC MD
MD
MD
WV
WV
WV
WV
WV
WV
VA
VA
VA
VA
VA
VA
KY
KY
KY
KY
KY
KY
NC
NC
NC
NC
NC
NC
AZ
AZ
AZ
AZ
AZ
AZ
OK
OK
OK
OK
OK
OK
NM
NM
NM
NM
NM
NM
TN
TN
TN
TN
TN
TN
AR
AR
AR
AR
AR
AR
SC
SC
SC
SC
SC
SC
MS
MS
MS
MS
MS
MS
TX
TX
TX
TX
TX
TX
AL
AL
AL
AL
AL
AL
LA
LA
LA
LA
LA
LA
GA
GA
GA
GA
GA
GA
FL
FL
FL
FL
FL
FL
AAEL [$ M]
Alaska
Ov er 500
100 to 500
50 to 100
10 to 50
Less than 10
Hawaii
Average Annual Earthquake Loss per
Capita for 35 Metropolitan Areas
Seattle
Boston
Cincinnati
Indianapolis
Columbus
WA
WA
WA
WA
WA
WA
Providence
MT
MT
MT
MT
MT
MT
Takoma
ND
ND
ND
ND
ND
ND
VT
VT
VT
VT
VT
VT
OR
OR
OR
OR
OR
OR
ID
ID
ID
ID
ID
ID
Portland
Reno
MN
MN
MN
MN
MN
MN
SD
SD
SD
SD
SD
SD
Boise
Cleveland
WI
WI
WI
WI
WI
WI
NY
NY
NY
NY
NY
NY
Salt Lake
City
CA
CA
CA
CA
CA
CA
UT
UT
UT
UT
UT
UT
San
Francisco
Provo
MA
MA
MA
MA
MA
MA
CT
CT
CT
CT
CT
CT
MI
MI
MI
MI
MI
MI
WY
WY
WY
WY
WY
WY
NV
NV
NV
NV
NV
NV
ME
ME
ME
ME
ME
ME
Newark
IA
IA
IA
IA
IA
IA
NE
NE
NE
NE
NE
NE
IN
IN
IN
IN
IN
IN
IL
IL
IL
IL
IL
IL
OH
OH
OH
OH
OH
OH
Las
Vegas
St. Louis
OK
OK
OK
OK
OK
OK
Little Rock
TX
TX
TX
TX
TX
TX
San Diego
LA
LA
LA
LA
LA
LA
TN
TN
TN
TN
TN
TN
SC
SC
SC
SC
SC
SC
MS
MS
MS
MS
MS
MS
AL
AL
AL
AL
AL
AL
Hartford
New
York
Baltimore
NC
NC
NC
NC
NC
NC
Asheville
Columbia
Memphis
Atlanta
NM
NM
NM
NM
NM
NM
Los Angeles
Louisville
AR
AR
AR
AR
AR
AR
AZ
AZ
AZ
AZ
AZ
AZ
VA
VA
VA
VA
VA
VA
KY
KY
KY
KY
KY
KY
MO
MO
MO
MO
MO
MO
KS
KS
KS
KS
KS
KS
NJ
NJ
NJ
NJ
NJ
NJ
WV
WV
WV
WV
WV
WV
Kansas City
CO
CO
CO
CO
CO
CO
PA
PA
PA
PA
PA
PA
MD
MD
MD
MD
MD
Charleston
GA
GA
GA
GA
GA
GA
Jackson
FL
FL
FL
FL
FL
FL
Savannah
AAEL [$ per Capita]
Anchorage
Albuquerque
Alaska
100 to 500
50 to 100
10 to 50
1 to 10
Less than 1
Honolulu
Hawaii
Cost-Benefit Analysis
• Benefit-cost ratio:
– Calculate annual benefits
– Multiply by lifetime
– Calculate projected cost of
special earthquake construction
– Take ratio to get benefit/cost ratio
• Would it be better to spend this money on
new schools, hospitals, etc.
Takes big quakes to test
predictions
$10,000 bill,
• Several natural biases
Discontinued in
– Insurance companies like high rates 1969,
– Cities like perception of low risk Salmon Chase
is pictured
– Scientists like to make changes to status quo
• Real process is that everybody makes a
guess, which is either verified or
contradicted by real quakes
– Often decades later
Global quakes per year
GutenbergRichter
Relationship
1 magnitude 8 or bigger (or a little less)
10 magnitude 7 or bigger
100 magnitude 6 or bigger
1000 magnitude 5 or bigger
etc…
Average data from 1904-1980
Kanamori and Brodsky, 2001
Definitions
• Sequence
– Set of quakes that are related
• Foreshock
– Quake followed by a bigger quake in same
sequence
• Mainshock
– Biggest quake in a sequence
• Aftershock
– Quake after the biggest quake in a sequence
• Corollaries
– One never knows that an event is a foreshock
until the mainshock comes along
– Aftershocks can turn into foreshocks
Differences between
mainshocks, foreshocks and
aftershocks
•NONE!
Mainshock
• Largest earthquake in a sequence
• Larger mainshocks strain larger
volume of rock, have more
aftershocks
• Foreshocks and aftershocks usually
at least 1 magnitude unit smaller
than mainshock
Foreshocks
• Smaller earthquakes that
precede the mainshock
– often by just hours
• Few in number
– only half of mainshocks have
even one foreshock
• Near mainshock hypocenter
– part of the nucleation process
Haicheng 1975
Magnitude of
earthquakes over
time
Foreshocks
(Days)
Aftershocks
• smaller earthquakes following the
largest earthquake of a sequence
(the mainshock) near mainshock
rupture zone
–
–
–
–
follow almost all shallow earthquakes
cover ruptured area
can number in thousands
can last for years or decades
• aftershocks of Northridge M 6.7 are still
occurring
– The most predictable (and therefore
well-studied) earthquakes
Cause of aftershocks
• Every time there is an earthquake, the
volume of rock around the rupture is
strained, that is, twisted or squeezed.
• Sometimes, the strained rock breaks.
• Often, it takes a while for it to break, so
the aftershocks may appear seconds to
years after the causative quake.
• But we don’t know for sure why there is a
delay.
– Static fatigue
– Visco-elastic relaxation
– Diffusion processes (fluids?)
Static stress
triggering
Earth is stretched or
compressed
by fault movement (as
in elastic
rebound models)
Some earthquakes
near fault
Some where stress
level was raised
Fewer where stress
level dropped
Dynamic Triggering
• Shaking, rather
than just long-term
loading, triggers
aftershocks
• Evidence from
earthquakes with
strong directivity
Gomberg et al., 2003
Aftershocks tell us about
mainshock
• Seismologists estimate the area
of rupture by mapping aftershock
locations
– Aftershocks cover the rupture area
and may expand slightly outside of it
• Obtain length and width of faulted area
=> magnitude of mainshock
• Obtain orientation of faulted area
Loma Prieta example
•
•
•
•
40-50 km long aftershock zone
Extends to 12 km depth
Slightly dipping to southwest
Again, focus near middle of bottom
of rupture zone
• Loma Prieta had two M 5 foreshocks
6 months earlier very near focus
Loma Prieta aftershocks
Along fault view
Cross-section
Map view
N
Ellsworth paper
Distribution of sizes
• Like for mainshocks, there are many
more small aftershocks in a
sequence than big aftershocks
• If mainshock has M 6
– 1 or 2 aftershocks with M 5 to 6
– 10’s of M 4 to 5
• If mainshock has M 8, an M 7
aftershock is likely
Omori’s
Law:
Aftershock
frequency
Jones pamphlet
Ignores
foreshocks
Real Data
Magnitude
7.5
7
6.5
6
5.5
5
4.5
4
3.5
3
2.5
Landers
Earthquake
Date
0
20
40
Omori’s Law
• Number N of aftershocks decreases with time t
• Mathematically, rate of aftershocks follows
N ~ C/t
where: N is the number of earthquakes
t is time
C is a constant
• Likelihood of getting a big earthquake decreases
with time
– Combine Gutenberg-Richter and Omori’s Law
• Most happen within first few weeks, many within
first day or two
Omori’s Earthquake
The decay of
aftershock activity
following the 1891
Nobi, Japan,
earthquake
… for over 100 years!
Number
of
Earthquakes
Utsu (2002)
Prediction topics
• As we just saw
– Foreshocks can
be useful
• Nutty amateur
web pages
• Scientific efforts
not much more
successful
To make an earthquake
prediction need to state:
• Time interval in which quake will
occur
• Region in which quake will occur
• Magnitude range of predicted quake
– Small quakes occur more commonly
– Easy to predict there will be magnitude
3 somewhere in Southern Ca. next
month, but not useful
To be able to predict there
must be precursors
• Sometimes there are,
• Sometimes not there or perhaps too
small to observe
• Need many decades (several
centuries?) to study the patterns
because there is a lot of
randomness
Japan downplays
prediction
Nature, 1999
• Earthquake research in Japan should
focus on understanding the mechanism of
earthquakes, rather than predicting them,
according to an advisory body to the
Japanese prime minister. This shift is
needed to develop new disaster
prevention technologies.
• Although the prediction program has
shifted its focus to making long-term
forecasts, there is still no guarantee that
this is actually possible.
Possible precursors
• Change (increase or decrease) in
number of earthquakes
– For example, foreshocks
– Difficult to distinguish such changes
from random variations
•
•
•
•
Ground uplift or tilt
Radon emission
Electrical resistivity
Seismic wave velocity
French machine
Clustering of seismicity
• Whenever there’s a quake, it
becomes more likely that more
quakes will come soon
• 10% chance that any quake will be
followed by a bigger quake
• With passing time (and no quake),
odds return to normal
Star
clusters
Normal
Dilatancy
• Swelling of
rock as it
approaches
failure
Just before failure
Rock
crusher
Footsteps in sand
• It is well known that when
you walk on wet sand on
the shore, your footsteps
get dry.
• This is similar to what
occurs in rock dilatancy.
• As a deformation is
imposed on the sand,
space between grains
increase, allowing for
upper water to invade the
sand.
How rock properties could
produce precursors
I
II
III
IV
Pg 193 Brumbaugh
Mechanical model of
cracking
Stress
Strain
I
II
III
V
Dilatancy
P-wave velocity
Ground uplift
Radon emission
Electric resistance
Number of quakes
Bolt
Palmdale Bulge -
Example of the Problem
• Date: August 29, 2002 at 02:19:10 From: *deleted*,
• Subject: 24 to 72 hrs, Los Angeles, 8+ maybe 9, 100%
• There will occur a magnitude 8+ quake taking
place in Los Angeles, actually Parkfield to San
Bernardino and then around the turn down to
Bombay Beach, Salton Sea.
• It will be the worse earthquake in American
History
• This is NOT a prediction. Repeat, This is NOT a
prediction.
• Instrument records have revealed major
magmatic movement for 400 miles on the east side
of CA, and the tilt and movement will trigger the
San Andreas and possibly the San Jacinto,
Elsinore and other faults.
• If I am wrong, may God forgive me.
Follow-up post
• Thanks to my hysteria, I've incorrectly
posted the date that this will occur. It
could be days to a few weeks as the MBP
has NOT yet occurred. The SPI take place
first then the MPB takes place just before
the quake 24 to 72 hours.
• However the magnitude and area is
correct. It will be well over 8+
Biological Earthquake
Prediction
• Charlotte King
– http://www.viser.net/~charking/
• “Unusual” ability to hear ULF, VLF,
and ELF sounds
• For example, she claims sounds
change pitch or rhythm, then a
quake over 5.0 happens in 72 hours.
Are you sensitive?
• If you walk into a room and bump into
furniture or you go to pour some juice and
miss the glass, or go to put sugar in your
tea and end up with sugar on the table,
you may be clumsy, or you may be a
potential biological sensitive..
• “Do you all the sudden crave popcorn..
you don't know why.. you just want it..
– this is a definite precursor to earthquakes or
volcanic eruptions...
• the event will hit within 12-24 hours.”
Charlotte’s details
• [She] discovered that if a quake was
building in volcanic areas, the
headache was a full-blown migraine.
[She] had vertigo problems and her
heart was hurting with small, sharp
electrical-like shocks.
• Her accuracy rate is “85-90+% for
quakes over magnitude 6; 100% for
Mt. St. Helens; and near 100% on
other volcanoes, for time, magnitude
and location.”
http://www.sollog.com/
Quakes00.shtml
Sollog's 2000 Easter Quake Prophecy
Hannakah Quake strikes where Sollog GUARANTEED!
XMAS QUAKE strikes where Sollog GUARANTEED!
Line
of
Sollog
Sollog’s books
More Sollog
Ennis’ mug shot from the
Broward County Sheriff's
Office, 2005.
• The recent earth quake predictions made
by Sollog that occurred on the exact
dates he gave, “have been estimated by
seismology professors at odds up to 3.65
Billion to 1”.
• Sollog says the reason he is so accurate,
is to warn that
•
Nuke Terrorism is near!
• Subscribers to the Usenet newgroup
alt.usenet.kooks named him “Kook of the Month
for June 1998
Another Prophet
Gordon-Michael
Scallion
• Some predictions from 1995
– We can check for accuracy:
– three new plagues,
– super-mega earthquakes will hit the Ring of Fire,
– Palm Springs will get a 9.0 earthquake (+/- 0.5),
– eruption of twelve volcanoes worldwide,
• reduced sunlight, physical and emotional problems, and
– beginning stages of Armageddon.
http://www.nhne.com/specialreports/srscallion95.html
Inscrutable
junojuno2.tripod.com/earthquakes.html
Eclipse then earthquake?
http://www.damien.edu//lee/
lee_english.html
• … cycles of earthquakes in
relationship to solar and lunar
eclipses have been charted down to
the minute.
• There are consistent patterns that
show up .
Eli
Eli’s results
• On July 20 1963, Anchorage Alaska was visited
on that day by a solar eclipse.
– Eight months latter a 9.2 earthquake strikes Anchorage
leaving a path of devastation.
• In New Madrid, a solar eclipse took place 3
months before the quake over the great lake
Michigan and Lake Erie.
– These two lakes have a fault connection on the New
Madrid Fault and they hold the key to understanding
the New Madrid fault especially Lake Erie.
• In Feb. 26, 1979 a solar eclipse took place
over Mt. St. Helens volcano in the Pacific
North West.
– 15 months later it erupts.
http://quake.exit.com/
Quake
cloud!
Northridge
cloud
Around 7:15 a.m., January 8,
1994 the cloud suddenly
appeared, shaped like sword,
rising like a launching rocket
in the northwest sky from
Pasadena
Nine days later, an M 6.7 quake
struck, supposedly without
warning!
Another
• 1/12/99: “The world has
been void of M6 quakes
for too long. Expect an M6
or larger in China or New
Zealand.”
• 1/27/99: “Well, the M6 hit
in Columbia, not in China,
and unfortunately in a
populated area. Damage
is severe.”
A bigger
nuisance
• James O. Berkland
– SYZYGY...An Earthquake Prediction Newsletter
– http://www.syzygyjob.org
– I am a country boy who grew up in the Valley of
the Moon, in Sonoma County, north of San
Francisco.
– I was the first County Geologist for Santa Clara
County from 1973 until my retirement in 1994.
– I have been recognized in about eight Who’s
Who Publications.
Berkland example
• For the May 3-10, 2000 window I make the
following predictions, with 80%
confidence:
– Within 2-degrees (140 miles of San Jose, CA)
there will be a 3.5-6.0M earthquake;
– Within 140 miles of Los Angeles, CA there will
be a 3.5-6.5M earthquake.
– In Oregon and/or Washington there will be a
3.0-5.0M earthquake.
– Somewhere on Earth (probably within the
Pacific Ring of Fire) there will be a major
event of at least 7.0M.
More from web page
• The 'Earthquake Lady', Clarisa
Bernhardt, phoned me last week
with a psychic seismic concern
about California for April 15-May 15,
2000.
Basis of Berkland’s predictions: Just
as water is pulled and deformed by
the moon, the solid earth is too. Solid
earth tides are highest when sun and
moon are aligned.
Many studies have been done on this subject, and only
a very, very small effect has been found.
Warning (from Drudge page):
Planetary Alignment
• Idea is that gravity from all these bodies will
“pull” stronger tides than usual.
• Planetary alignment fears are ancient
– First recorded prediction in 300 BC
– In February 1954, a similar alignment led the
Chinese to restart their calendar at year 0
– In 1962, panicked people surrounded Griffin
Observatory
– In 1982, “Jupiter Effect” was published
• Predicted California earthquake
Prediction of
ultimate disaster
• Not that infrequently, Jupiter, Mars,
Mercury, Saturn and Venus will appear
tightly clustered in the sky
• No astronomical significance to the
pileup. It is just a "pretty coincidence."
• In the months before the May 2000
lineup, some thought it foretold
widespread catastrophe.
Picture
of 2000
alignment
DisasterRelief.org
The claim in 2000
• Geological Armageddon
DisasterRelief.org
– You’d have volcanism going on globally.
– Earthquakes beyond the scale of anything
Richter ever dreamed of.
– Tsunamis hundreds of feet high.
– The civilizations that built the pyramids
disappeared because of planetary
alignment.
• Richard Noone
– 5/5/2000, Ice: The ultimate disaster
Best guess
by scientists
Duncan Agnew
• Some work by me, a guy at UCSD, a woman in Japan, and
mostly my ex-student Prof. Elizabeth Cochran
• Looked at lunar tides, the biggest tide
• At most favorable times for quakes, the risk of a quake is
about 1% higher than average most places
• Risk is not noticeably different than normal
• A few places around the Pacific, when tide goes down 3+
meters, earthquakes can be twice as likely as average
New Berkland
Biography
• By Cal Orey
• Amazon.com
Sales Rank:
peaked at
#79,834 in
Books
• I added a
review.
China discouraging
predictions
• From journal Nature, January 28th, 1999
• Unofficial earthquake warnings
– 30 in the last 3 years
– Brought factories and business to a halt
– None has been accurate
• New law
– Requires high standard of scientific reasoning
– Or else predictors will be penalized
– Being enforced with latest earthquake
A view to kill - James Bond
• An earthquake sensitive
region in Northern California,
the Hayward Fault, is key to
Zorin's attempt to destroy
Silicon Valley.
• Zorin intends to destroy
Silicon Valley and all its
technology by causing
earthquakes to swallow the
Valley.
• His evil plan is to gain control
of the world's supply of
microchips.
Not
likely
We don’t know where to
trigger quakes, and can’t
exert enough force to
matter
Superman
the movie
• Lex Luthor sends two nuclear missiles to strike a
stress point on the San Andreas Fault resulting
in the western coast of California sinking into the
ocean.
• That would turn the desert land he had just
purchased into coastal property, making Luthor
a very wealthy man.
• Missiles set off earthquake, but Superman flies
backward to turn back time, so he can thwart the
effort.
Real predictions
• Parkfield seemed to 22 year repeat time
– Was supposed to happen in 1989 or so
– Lots of equipment put out
• Broke in 1857, 1881, 1901, 1922, 1934,
1966, ?
• Or were those really similar events?
• We finally got the quake Sept 2004
• Not hard to find spurious patterns
– Like presidential assassinations
Parkfield scorecard
• Right area broke
– Hole in the seismicity pattern
– Mostly same as in some previous events
– Maybe
•
•
•
•
•
Well-recorded
Broke the wrong way
20 years late
No precursory signals
Messed up drilling experiment
– Most definitive instruments not yet in place,
unlikely to capture mainshock now
Last two Parkfield events
American Presidents
• 1861-1865: A. Lincoln
– 1865 April 14, Wounded by assassin John Wilkes Booth; 1865
April 15, died early in the morning from wound in Washington,
D.C.
• 1881-1884: J. Garfield
– 1881 July 2, Wounded by assassin in Washington, D.C., 1881
September 19, died from wounds at Elberon, New Jersey
• 1897-1901: W. McKinley
– 1901 September 6, Shot by an assassin in Buffalo, New York,
September 14, died from wounds in Buffalo
• 1921-1924 W.G. Harding
– 1923 August 2, died in San Francisco
• 1941-1945 F.D. Roosevelt
– 1945 April 12, died at Warm Springs, Georgia
• 1961-1964: J.F. Kennedy
– 1963 November 22, Assassinated in Dallas, Texas
• 1981-1984: R. Reagan
– 1981 March 30, wounded in an attempted assassination
• 2001-2004 GW Bush? nope
A more successful prediction
• 1975 Haichung quake
– Predicted
– But there were many M=6 foreshocks
• So it was an easier than usual quake to predict
• 1976 Tangshan quake
– No warning
– Probably killed 750,000 people
• But official toll was 250,000 deaths
• Now we do long-term probabilities
– Lecture next week
Basis of M8
• different measures of
intensity in earthquake
flow, its deviation from the
long-term trend, and
clustering of earthquakes
• 5-year windows of TIP: Prof. Keilis-Borok
Works at UCLA
“Time of increased
and in Moscow
probability” assessed
every 6 months
• Inside the TIP zones, 2nd
method tries to further
limit area of alarm
M8 - a real forecast
TIP zone circles
Refined
estimates of
quake location
In fact
• 2004, there was a prediction for
Mojave-San Diego area
– M6.4 to 7.4
– Chance was estimated at 50% in next 9
months
– 3 different groups, not official
• Prediction for the Bay Area
– M6.5+, hit in 2003, another “hit” for
Japan
• The effectiveness of these methods is
still not proven
Done for the day
Fly UP