49134-Earthquake eng v0.pdf

8/9/2019 49134-Earthquake eng v0.pdf

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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:[email protected]:(02) 9514 2651 Fax: (02) 9514 2633


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Earthquake Engineering Seismicity

Earthquake Faults and Waves

Structure of the earth

Earthquake size


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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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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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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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Measure and record earthquakes


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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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49134-Earthquake eng v0.pdf

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