History of seismology—the ancients
• Bronze age cultural
History of seismology
•
History of seismology—the ancients
• Other global ideas
• Aristotle: quakes
•
produced by collision
of subterranean
winds, described in
“Meteorologica”,
~340 BC
Wind/gas model
lasts until ~1700’s (!)
History of seismology—the West
• Much Western
•
science in seismically
inactive regions, so
seismology slow to
grow in the West
Lisbon earthquake,
1755 kills >70,000.
Starts “modern” era
of seismology.
centers (Megiddo)
collapsed over ~50
years…may have
been string of
earthquakes
So earthquakes were
prevalent. What did
people think about
them?
History of seismology—the East
• First “seismoscope”
•
•
built by Chinese in 132
BC
Chinese have
recorded every
moderate to large
quake since 780 BC
Japan catalog
complete since 1600,
less complete since
416 AD
Lisbon, 11/1/1755: the first modern
earthquake
Marquis sent out questionnaire to parishes asking
about aftershocks, earthquake duration, damage,
well water, animal behavior, and aftershocks.
1
Lisbon, 11/1/1755: the first modern
earthquake
Lisbon, 11/1/1755: the first modern
earthquake
Astronomer John Mitchell calculates velocity of
seismic wave to be ~500 m/s (slow, but not
impossible)
Marquis
Astronomer
Enormously
sent John
influential
out questionnaire
Mitchell
in European
calculates
to parishes
religion
velocity
asking
and
of
about
seismic
aftershocks,
thought
wave (Rousseau,
to be
earthquake
~500Voltaire,
m/sduration,
(slow,
Kant)
but
damage,
not
well water, animalimpossible)
behavior, and aftershocks.
History of seismology
History of seismology
• Seismological theory develops
• Seismological theory
develops in 1800’s
• 1883—G. K. Gilbert
in 1800’s
•1821-22, equations for elasticity
(Navier and Cauchy)
•1830—Poisson calculates that 2
•
types of waves (only) travel
through homogeneous solids (P
and S waves)
1859—Robert Mallet associates
quakes with “the breaking up and
grinding over each other of rocky
beds”
History of seismology
• Development
of
instrumentation
• 1875—first
seismometer
(detects and records
•
•
•
•
•
earthquake vibrations) built by
Filippo Cecchi in Italy
1889—first distant recording of
earthquake (quake in Japan,
recorded in Germany)
1892—John Milne leads
development of first portable.
Starts era of global seismology
1906—dozens of seismographs
around the world record SF
quake.
A great example from 1964.
•
associates earthquakes with
faults!
1887, 1911—Lord Rayleigh
and Augustus E. H. Love
demonstrate existence of
waves at free surface
(surface waves)
1906—H. F. Reid uses
offsets from SF quake to
develop elastic rebound
theory
History of seismology
• Development
of
instrumentation
• 1875—first
seismometer
(detects and records
•
•
•
•
earthquake vibrations) built by
Filippo Cecchi in Italy
1889—first distant recording of
earthquake (quake in Japan,
recorded in Germany)
1892—John Milne leads
development of first portable.
Starts era of global seismology
1906—dozens of seismographs
around the world record SF
quake.
A great example from 1964.
2
More advances in instrumentation
• Development of digital instruments
• Development of ocean-bottom instruments
• Development of broadband instruments
• Development of world wide web
• Advances in computational power
History of seismology
• Major discoveries using
seismic waves
•1906—Richard Oldham
discovers the core
•1909—Andrija Mohorovičić
discovers the Moho
•1936—Inge Lehmann
discovers the inner core
Other discoveries/developments
Other discoveries/developments
• 1935—Charles
Richter
develops “Richter scale”
• 1935—Charles
Richter
develops “Richter scale”
•
•
•
•
•
for measuring strength of
S. Californian
earthquakes
1946—First nuclear
explosion recorded by a
seismograph
1969—seismometer
placed on moon
1977—Moment magnitude
scale proposed by Hiroo
Kanamori
1996—CTBT established.
Need for global seismic
monitoring to confirm
adherence to treaty
Other discoveries/developments
•
•
•
for measuring strength of
S. Californian
earthquakes
1946—First nuclear
explosion recorded by a
seismograph
1969—seismometer
placed on moon
1977—Moment magnitude
scale proposed by Hiroo
Kanamori
1996—CTBT established.
Need for global seismic
monitoring to confirm
adherence to treaty
Other discoveries/developments
• 1935—Charles
Richter
develops “Richter scale”
• 1935—Charles
Richter
develops “Richter scale”
•
•
•
•
•
for measuring strength of
S. Californian
earthquakes
1946—First nuclear
explosion recorded by a
seismograph
1969—seismometer
placed on moon
1977—Moment magnitude
scale proposed by Hiroo
Kanamori
1996—CTBT established.
Need for global seismic
monitoring to confirm
adherence to treaty
•
•
•
for measuring strength of
S. Californian
earthquakes
1946—First nuclear
explosion recorded by a
seismograph
1969—seismometer
placed on moon
1977—Moment magnitude
scale proposed by Hiroo
Kanamori
1996—CTBT established.
Need for global seismic
monitoring to confirm
adherence to treaty
3
History of seismology
• Often driven by major earthquakes
•San Francisco, 1906—faulting/elastic rebound
•Tokyo, 1923—engineering
•Chile, 1960—Earth normal modes
•Haicheng, 1975—prediction?
•Mexico City, 1985--Amplification
•Northridge, 1994--$$
•Kobe, 1995—more engineering
•Denali, 2002—triggered seis/directivity
•Sumatra, 2004—tsunami, long period waves
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