Post on 01-Jun-2018
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49134 Structural Dynamics & Earthquake Engineering
Introduction to
Earthquake Engineering
Faculty of Engineering & IT
Lecturers: A/Professor Jianchun LI
Contact Information:Room: CB11.11.116 Email:Jianchun.Li@uts.edu.auPh:(02) 9514 2651 Fax: (02) 9514 2633
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49134 Structural Dynamics & Earthquake Engineering
Earthquake Engineering Seismicity
Earthquake Faults and Waves
Structure of the earth
Earthquake size
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49134 Structural Dynamics & Earthquake Engineering
Earthquakes What ?
The earth rumbling, Groundshaking
One of the most violent naturalphenomena
How ? When plates or Rocks within
the earth suddenly break orshift under stress
Some facts 500,000 quakes per year
Only small fraction can be feltby human
10,000 people killed on averageevery year in the last century
Deadliest earthquake happenedin China in 1557, an estimated830,00 people killed
10/8/2014 3
Japan
IndiaChile
Spain China
Iran
Central
America
The Pyne Gould Corp. building, NZ, 2011
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Earthquakes
Most earthquakes
occur along fractures inthe earths crust call
faults.
Most Faults occur alongthe edges of major
plates that make up the
earths shell.
Intraplate earthquake
Interplate earthquake
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Where do earthquakes occur
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What Occurs Earthquakes
Plate tectonics
A process that earthplates are constantly
moving and interacting
Earthquake
Release of energy and a
great burst of seismic
waves which follows
California St Andreas Fault
[Source from ]
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49134 Structural Dynamics & Earthquake Engineering
The San Andreas Fault is the sliding
boundary between the Pacific Plate andthe North American Plate
It slices California in two from Cape
Mendocino to the Mexican border.
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49134 Structural Dynamics & Earthquake Engineering
Types of Earthquake Faults
Definition of Fault Orientation, and of the basic types of fault displacement[Adapted from Earthquake by Bruce A bolt, W.H. Freeman and Company 1988]
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Form of the Earth Motion
Forms of ground motion near the ground surface in the four types of earthquake waves.[From Bruce A. Bolt, Nuclear Explosions and Earthquakes: The Parted Veil (San Francisco: W.H.FreeMan and Company.
Copyright1976.]
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49134 Structural Dynamics & Earthquake Engineering
Measure and record earthquakes
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49134 Structural Dynamics & Earthquake Engineering
Ground and Structural Damage
Bedrock with high
magnitudeGenerally the safest place to build
to avoid earthquake damage.
However, high magnitude
earthquakes may cause damage
such as cracks in buildings,
shattered windows andcrumbling of structure joints.
Landfill with high
magnitudeOne of most dangerous places to
be during the high magnitudeearthquakes. Landfill makes
ground act like liquid. The Once
solid ground is shaken at its
resonance ( cause amplification)
and appears move like thick soup.
Fault Zone with high
magnitudeBuildings on active fault zone are
likely to be in great danger during
earthquakes. May be major
rupturing along the fault as wellas significant displacement.
Buildings on the fault zone may
experience cracking, shearing and
displacement and some may
collapse during severe quakes.
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Richter Magnitude
Empirical Measure amount of strain energy released
Logarithm (base 10)
Measure earthquake size
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Question on Richter Magnitude
How many time is a ML=6
earthquake stronger than aML=5 earthquake?
M logE E E1/E2
1 13.3 1.99526E+13
2 14.8 6.30957E+14 31.62278
3 16.3 1.99526E+16 31.62278
4 17.8 6.30957E+17 31.62278
5 19.3 1.99526E+19 31.62278
6 20.8 6.30957E+20 31.622787 22.3 1.99526E+22 31.62278
8 23.8 6.30957E+23 31.62278
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Charles F. Richter introduced the Richter scale in 1935.
The Richter magnitude is denoted as ML. It is also called the " localmagnitude." It is based on the maximum excursion of the needle on the"Wood-Anderson seismograph." The Richter scale was intended for
southern California earthquakes only.The Richter scale is a logarithmic scale. The earthquake wave displacementamplitude increases by a factor of 10 for every 1 unit increase of the Richtermagnitude.
The same 1 unit increase in magnitude, however, corresponds to an
increase of approximately 32 times the earthquakes energy. The magnitude calculation depends on two parameters:
1. The maximum displacement indicated on the Wood-Andersonseismograph2. The distance from the focus to the seismograph
For example, a 23 mil limeter displacement measured at a station 210
kilometers from the focus would have a value of ML = 5.0. A maximum displacement of 2.3 millimeters at this same station and
distance would correspond to ML = 4.0.
Notes on Richter scale
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