CI 5995 Engineering Seismology

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CI 5995 Engineering Seismology

• Lecture 1 Introduction

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Hours
Class Mon 1250 - 145 Wed 1250 -
240 Office Hours Wed 3 - 430 Classroom
CI 110
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Course Outline
Plate tectonics and earthquakes seismic
instrumentation, the earthquake source wave
propagation source, path and site effects
directivity ground motion estimation and
characterisation. hazard assessment the effect
of earthquakes on the built environment
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Schedule for a CI 5995 - 15 week course, 3 hours
per week 1st Semester 2005/6 Pre-requisite
Dynamics, Calculus Expected technical writing s
kills, familiarity with Matlab (timeseries),
basic understanding of calculus, Fourier
Transforms Week 1 Introduction to the hazards
of earthquakes strong ground motions, tsunamis,
landslides, liquefaction. Review of plate
tectonics. Seismic hazard in Puerto Rico and
beyond. Maths review Fourier Transforms Week
2 Single degree of freedom dynamics, damped
vibrations. Convolutions, Greens
Functions. Week 3 A seismic station sensors
and dataloggers. Poles and zeros for sensor
response. Mechanical and digital sensor design
and performance. Week 4 Interpretation of
Seismic Records acceleration, velocity and
displacement. Issues with strong ground motions,
and record parameterisation. Week 5 Theory of
wave propagation Body waves Week 6 Theory of
wave propagation Surface waves
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Schedule for a CI 5995 - 15 week course, 3 hours
per week 1st Semester 2005/6 Pre-requisite
Dynamics, Calculus Expected technical writing
skills, familiarity with Matlab (timeseries),
basic understanding of calculus, Fourier
Transforms Week 7 Building response. Issues for
shear wall, moment frames, braced frames, base
isolated structures. Woodframes, un-reinforced
masonry, adobe. Week 8 Hazardous ground
motions directivity, fling effects. Week 9
Soil effects ground motion amplifications,
liquefaction. Week 10 Earthquake source
physics. Seismic moment, focal mechanism. Tsunami
generation. Week 11 Wrap-up Seismic Hazard
Analysis Week 12 Introduction to final
project Week 13 Final Project Week14 Review
for final exam.
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Teaching/Grading Plan
Language English (sorry), hopefully
interactive Attendance compulsory Homeworks
every week, handed out Wednesday, due
Wednesday Exams midterm, final Project Grading
scheme midterm 20 final 40 project
20 homeworks 20 All exams/HW/project are
open book
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Final Project
A final project, based on determining the seismic
risk to a real or hypothetical structure in
Puerto Rico, will expose the student to current
literature in the field, and encourage the
student to think independently, in preparation
for thesis research.
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Class Texts
(no purchase required, all available from my
office for short durations) Lee, W.H.K,
Kanamori, H., Jennings, P.C., Kissinger, C.
(2002) International Handbook of Earthquake and
Engineering Seismology. Academic Press ?Shearer,
P. M. (1999) Introduction to Seismology.
Cambridge University Press. ? Kramer, S. L.
(1996) Geotechnical Earthquake Engineering.
Prentice Hall ? Stein, S. and Wysession, M.
(2003) An Introduction to Seismology,
Earthquakes and Earth Structure. Blackwell
Publishing Lay, T., and Wallace, T. C. (1995)
Modern Global Seismology. Academic Press Bolt,
B. A. (1993) Earthquakes. Freeman Havskov, J.,
and Alguacil, G. (2004) Instrumentation in
Earthquake Seismology, Springer Scherbaum, F.
(2001) Of Poles and Zeros Fundamentals of
Digital Seismology. Kluwer Academic
Publishers Aki, K., and Richards, P. G. (2002)
Quantitative Seismology, 2nd Edition,
University Science Books
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Some Intro Questions

• What is an earthquake?
• What causes earthquakes?
• Why do earthquakes damage buildings?
• How do you reduce the damage caused to
• the built environment?
• How do you measure the size of earthquakes?
• How do you measure the damage potential
• of an earthquakes?

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Goals of the Class (1)

• After completion of the course, the student
  should
• gain an understanding and appreciation of the
  seismic hazard in
• Puerto Rico and across the globe.
• understand the complex mechanisms that govern the
  occurrence
• of earthquakes, and the generation of damaging
  ground motions.
• be familiar with the wide array of potential
  damage to buildings
• that can occur from ground motions.
• have familiarity with the systems, networks and
  methods
• routinely used to record, monitor and perform
  research
• on seismic motions.

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Goals of the Class (2)

• Ground motions are important to buildings
• How to measure
• How to parameterise
• How big are the motions
• Wave propagation and types
• Layering, basins, non-linear
• soil yeilding
• 6. Source effects - geometrical
• rupture physics

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Todays Class
Introduction to the hazards of earthquakes
strong ground motions, tsunamis, landslides,
liquefaction. Some Important Definitions Vulner
ability Degree of damage caused by various
levels of loading. The vulnerability may be
calculated in a probabilistic or deterministic
way for a single structure or groups of
structures. Seismic hazard Probability of
occurrence in a given location of, e.g.,
destructive earthquakes. Seismic exposure may
be used synonymously with seismic
hazard. Seismic risk Defined as
hazard  vulnerability, i.e., probability of
occurrence of loading of a certain magnitude
times the probability for damage caused by that
load. Risk may be expressed in terms of economic
costs, loss of lives or environmental damage per
unit of time. Hazard mitigation Utilizing
knowledge of seismic hazard and risk to reduce
potential damages and loss of life due to
natural hazards earthquakes.
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How does the Earthquake Hazard Compare to Other
natural hazards?
In a typical year, the Earth generates about
12 million earthquakes, about 100 of which are
extremely damaging and disruptive to society
100,000 thunderstorms 10,000 floods Hundreds
of landslides and tornadoes Scores of
hurricanes, wildfires, volcanic eruptions,
droughts, and tsunamis At present, the average
economic toll from natural hazards in the United
States reaches 52 billion per year---1 billion
per week--- about one-third of the worldwide
toll. The average annual death toll is about
150,000 worldwide but is only about 200 in the
United States.
Major disasters of past year M9.3 Sumatra
Earthquake Tsunami 300,000 deaths M8.7
Sumatra Aftershock 1,000 deaths Typhoon in
Philippines 650 deaths Hurricane Jeanne in
Haiti 1,000 deaths
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Number of fatalities varies greatly every
yearHow about cumulatively?(note
disproportionate of deaths in Asia)
gt300,000
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1
3
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How about Economic Loss?
Most economic loss in Europe, USA
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But how often do these large events occur?
Similar inverse relation with frequency and size
of an event for all natural disasters
All Natural Disasters
Earthquakes
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The sources of energy for Natural Disasters
1996 Soufriere Hills
1995 Kobe
1.Heat from inside the earth (radioactive decay)
2.Heat from outside the planet(the sun)
3.Gravity 4.Impacts
1996 Yosemite
2002 Hurricane Mitch, Honduras
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The Earthquake Hazard - Where do Earthquakes
Occur / Why do Earthquakes Occur?
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• Earthquakes Occur due to Plate Tectonics
  earthquakes primarily occur at the interface
  between rigid
• plates on the earths surface, as there is
  relative motions between these rigid plates
• (relative motion caused by convection currents
  in the earths mantle)

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• There are four types of plate boundaries
• 1. Divergent boundaries -- where new crust is
  generated as the plates pull away
• from each other.
• 2. Convergent boundaries -- where crust is
  destroyed as one plate dives under another.
• 3. Transform boundaries -- where crust is
  neither produced nor destroyed
• as the plates slide horizontally past each other.
• 4. Plate boundary zones -- broad belts in
  which boundaries are not well defined
• and the effects of plate interaction are unclear.

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• Seismic Hazards
• Ground Shaking
• Structural Hazards
• Liquefaction
• Landslides
• Retaining Structure Failures
• Lifeline Hazards
• Tsunami and Seiche Hazards

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• Seismic Hazards
• Ground Shaking
• Structural Hazards
• Liquefaction
• Landslides
• Retaining Structure Failures
• Lifeline Hazards
• Tsunami and Seiche Hazards

• Seismic waves emanate from source, eventually
  reach surface
• Depending on
• a. source conditions (size, orientation),
• b. path conditions (depth, distance and azimuth,
• and structural
  characteristics of rock the
• waves travel through)
• c. site conditions (local rock layering,
  immediate
• soil conditions, 3-D
  basin/hill topography),
• the severity of ground shaking can vary
  enormously.
• Largest events can cause catastrophic shaking for
  many minutes
• Ground Shaking actually causes all the other
  hazards

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• Seismic Hazards
• Ground Shaking
• Structural Hazards
• Liquefaction
• Landslides
• Retaining Structure Failures
• Lifeline Hazards
• Tsunami and Seiche Hazards

• Typically most dramatic images, most deaths and
  economic loss from an earthquake are caused by
  structural collapse
• Risk is dependent on quality of design and
  construction of infrastructure (un-reinforced
  masonry, adobe never expected to do well, but
  often well designed structures have failure)
• Current design practices focus on improving
  strength and ductility of structures

Olive View Hospital, San Fernando, 1971
Kyoto, 1995
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• Seismic Hazards
• Ground Shaking
• Structural Hazards
• Liquefaction
• Landslides
• Retaining Structure Failures
• Lifeline Hazards
• Tsunami and Seiche Hazards

Northridge, 1994

• Typically most dramatic images, most deaths and
  economic loss from an earthquake are caused by
  structural collapse
• Risk is dependent on quality of design and
  construction of infrastructure (un-reinforced
  masonry, adobe never expected to do well, but
  often well designed structures have failure)
• Current design practices focus on improving
  strength and ductility of structures

Kyoto, 1995
Northridge, 1994
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Kobe, 1995

• Seismic Hazards
• Ground Shaking
• Structural Hazards
• Liquefaction
• Landslides
• Retaining Structure Failures
• Lifeline Hazards
• Tsunami and Seiche Hazards

• Spectacular failure of soils - complete loss of
  strength, flow like liquids
• Soil unable to support structures
• typically occurs in saturated sands
• Lateral failure
• Flow failure
• Sand boils

Kobe, 1995
Niigata, 1964
Kobe, 1995
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• Seismic Hazards
• Ground Shaking
• Structural Hazards
• Liquefaction
• Landslides
• Retaining Structure Failures
• Lifeline Hazards
• Tsunami and Seiche Hazards

Loma Prieta, 1989
Alaska, 1964

• Spectacular failure of soils - complete loss of
  strength, flow like liquids
• Soil unable to support structures
• typically occurs in saturated sands
• Lateral failure
• Flow failure
• Sand boils

Alaska, 1964
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• Seismic Hazards
• Ground Shaking
• Structural Hazards
• Liquefaction
• Landslides
• Retaining Structure Failures
• Lifeline Hazards
• Tsunami and Seiche Hazards

• Strong earthquakes often induce landslides, from
  liquefaction, or simply causing failure or
  marginally stable slopes
• Can bury entire towns
• Undersea can cause tsunami (eg 1999 Papua New
  Guinea)

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• Seismic Hazards
• Ground Shaking
• Structural Hazards
• Liquefaction
• Landslides
• Retaining Structure Failures
• Lifeline Hazards
• Tsunami and Seiche Hazards

• Important infrastructure can be damaged
  especially ports and harbours
• Strategic importance
• for aid/recovery in
• aftermath of earthquake

Kobe, 1995
Kobe, 1995
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• Seismic Hazards
• Ground Shaking
• Structural Hazards
• Liquefaction
• Landslides
• Retaining Structure Failures
• Lifeline Hazards
• Tsunami and Seiche Hazards

Tokyo, 1923
Loma Prieta, 1989

• Lifelines networks providing services required
  for commerce and health
• Include electric power, telecommunications,
  transportation, water, sewage, oil and gas
  distribution, water storage systems
• Systems include power plants, transmission
  towers, buried cabling, roads, bridges, harbours,
  airports, water treatment plants, reservoirs,
  elevated water tanks, buried water pipes, liquid
  storage tanks, buried gas and oil pipes municipal
  and hazardous waste landfills.
• Severe economic, environmental and health
  consequences if compromised
• Eg 1923 Great Kanto Earthquake, 1906 San
  Francisco fires
• 1989 Loma Prieta Bay Bridge failure

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• Seismic Hazards
• Ground Shaking
• Structural Hazards
• Liquefaction
• Landslides
• Retaining Structure Failures
• Lifeline Hazards
• Tsunami and Seiche Hazards

• Caused by rapid vertical seafloor movements (or
  impacts)
• In open sea, waves move rapidly, difficult to
  detect (under 1m high, 100s of km long
  wavelength)
• As reached shore, decreasing depth causes speed
  to increase, and height to rapidly increases
• Near vertical wall of water that rushes onshore,
  often far inland
• Seiches tsunami in enclosed bodies of water

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Indian Ocean Tsunami, Thailand, 2004
Niigata, 1964
Banda Aceh, before and after Indian Ocean
Tsunami, 2005
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Hazard Mitigation
The goal of our careers is to design safe
infrastructure, to mitigate these seismic
hazards Hazard mitigation Design buildings for
all possible ground motions! But also understand
the hazard Earthquake prediction statistical
forecasting Early warning tsunami, earthquakes