5.-Engineering-Seismologygggggggggyyyyyyyyy

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1. •Code: V129
•Subject CD: CE 417
•Schedule: 9:00-12:00 ThF
Geotechnical Earthquake
Engineering
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2. Engineering Seismology
•Engineering seismology is the study of
earthquakesand their effects on structures. It
bridges the gap between seismology and
earthquake engineering by providing
information to design earthquake-resistant
structures.
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3. Basic Concepts of Seismology
•Seismology is the scientific study of earthquakes
and the propagation of seismic waves through
the Earth. The field encompasses various
aspects, including the origin of earthquakes, the
mechanics of faulting, and the interpretation of
the seismic waves generated by these events.
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4. What is an Earthquake?
•An earthquake is the shaking of the Earth's
surface caused by a sudden release of energy in
the Earth's crust. This energy is typically released
due to the movement along faults, which are
fractures in the Earth's crust where blocks of the
crust have moved relative to one another.
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5. Magnitude vs. Intensity
•Magnitudemeasures the amount of energy
released at the source of the earthquake. The
most commonly used scale is the Richter scale,
though the moment magnitude scale (Mw) is
more widely used today as it is more accurate
for large earthquakes.
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6. Magnitude vs. Intensity
•Magnitude
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7. Magnitude vs. Intensity
•Magnitude
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8. Magnitude vs. Intensity
•Magnitude
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9. Magnitude vs. Intensity
•Magnitude
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10. Magnitude vs. Intensity
•Intensitymeasures the effects of an earthquake
at different locationson the Earth's surface,
typically using the Modified Mercalli Intensity
(MMI) scale. Unlike magnitude, intensity varies
with distance from the epicenter.
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11. Magnitude vs. Intensity
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12. 12

13. Seismographs and Seismograms
•Seismographsare instrumentsthat detect and
record seismic waves. They typically consist of a
mass suspended on a spring, with the mass
remaining stationary as the Earth moves during
an earthquake, thus recording the motion.
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14. Seismographs
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15. Seismographs and Seismograms
•Seismogramsare the records produced by
seismographs, displaying the amplitude of
seismic waves over time. They are crucial for
determining the location, magnitude, and depth
of an earthquake.
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16. Seismograms
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17. Seismograms
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18. Body Waves
•Body waves travel through the interior of the
Earth. They are divided into two types:
•P-waves (Primary waves):These are compressional
waves that cause particles to oscillate back and forth in
the direction of wave propagation. They are the fastest
type of seismic waveand can travel through both solid
and liquid materials.
•S-waves (Secondary waves): These are shear waves that
cause particles to oscillate at right angles to the direction
of wave propagation. They can only travel through solid
materials. 18

19. Surface Waves
•Surface waves travel along the surface of the
Earth. They are slower than body waves and
cause more damage to structures. There are two
main types of surface waves:
•Rayleigh waves:These waves cause the ground to
move in an elliptical motion. They are the slowest
type of seismic wave.
•Love waves:These waves cause the ground to move
horizontally back and forth. They are slightly faster
than Rayleigh waves.
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20. Seismic Hazard and Risk
•Seismic Hazardrefers to the probability of an
earthquake occurringin a given region and the
resulting ground shaking. It is typically assessed
through seismic hazard maps, which display
expected levels of ground shaking over a certain
period.
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21. Seismic Hazard and Risk
•Seismic Riskinvolves the potential
consequences of seismic hazards on human life,
infrastructure, and the economy. It considers
both the probability of ground shaking and the
vulnerability of structures.
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22. Engineering Seismology in Practice
•Engineering seismology applies the principles of
seismology to address practical engineering
problems. This includes the assessment of
seismic hazards, the design of earthquake-
resistant structures, and the development of
building codes and standards.
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23. Engineering Seismology in Practice
•SEISMIC SITE CHARACTERIZATION
•Understanding the local geological conditions is
crucial in predicting how an area will respond to
seismic waves. For instance, soft soils can amplify
seismic waves, leading to more intense shaking.
Engineering seismologists conduct site
investigations to determine the seismic response of
different soil and rock layers.
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24. Engineering Seismology in Practice
•SEISMIC MICROZONATION
•This involves dividing a region into zones that
have different potential levels of seismic
hazard. Microzonationmaps are used for
urban planning, helping engineers design
structures according to the specific seismic
risks of each zone.
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25. Engineering Seismology in Practice
•GROUND MOTION PREDICTION
•Predicting ground motion at a site is essential for
designing structuresthat can withstand
earthquakes. Ground motion prediction models
(GMPMs) estimate the expected seismic waveforms
based on factors like earthquake magnitude,
distance from the fault, and local site conditions.
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26. Engineering Seismology in Practice
•RESPONSE SPECTRA
•Engineers use response spectra to design buildings
and other structures. A response spectrum shows
the peak response (displacement, velocity, or
acceleration)of a structure as a function of the
structure's natural frequency. This allows engineers
to predict how different structures will respond to
seismic events.
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27. Engineering Seismology in Practice
•BUILDING CODES AND STANDARDS
•Engineering seismology informs the development
of building codes and standards, which set the
minimum requirements for designing and
constructingearthquake-resistant structures. These
codes are based on the latest scientific
understanding of seismic hazards and risk.
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28. Engineering Seismology in Practice
•POST-EARTHQUAKE ANALYSIS
•After an earthquake, engineering seismologists
analyze the event to understand its causes, the
effectiveness of existing structures, and what can
be improved in future designs. This analysis often
involves examining seismograms, ground motion
data, and the performance of buildings.
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29. Challenges and Future Directions
•Complexity of Seismic Sources: Understanding the complex
nature of seismic sources, including multifaultearthquakes
and induced seismicity, remains a challenge.
•Uncertainty in Ground Motion Prediction: Despite advances,
predicting ground motion accurately remains difficult due to
the variability in earthquake source mechanisms and local
site effects.
•Integration with Emerging Technologies: The integration of
new technologies such as AI, machine learning, and real-time
data analysis in seismic hazard assessment and risk
mitigation is an ongoing area of research.
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30. Major Earthquakes in the World
•1960 Valdivia Earthquake (Chile)
•Magnitude: 9.5 (Moment Magnitude Scale, Mw)
•Details: The largest earthquake ever recorded, it
caused widespread damage in southern Chile,
generated tsunamis that affected many coastal
areas across the Pacific, and led to thousands of
deaths.
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31. Major Earthquakes in the World
•1960 Valdivia Earthquake (Chile)
•Magnitude: 9.5 (Moment Magnitude Scale, Mw)
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32. Major Earthquakes in the World
•2004 Indian Ocean Earthquake and Tsunami
•Magnitude: 9.1–9.3 (Mw)
•Details: Originating off the west coast of northern
Sumatra, Indonesia, this earthquake triggered a
massive tsunami that affected 14 countries,
resulting in over 230,000 deaths.
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33. Major Earthquakes in the World
•2004 Indian Ocean Earthquake and Tsunami
•Magnitude: 9.1–9.3 (Mw)
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34. Major Earthquakes in the World
•2011 TōhokuEarthquake and Tsunami (Japan)
•Magnitude: 9.1 (Mw)
•Details: The earthquake off the coast of Japan
caused a devastating tsunami, leading to significant
loss of life, destruction, and the Fukushima Daiichi
nuclear disaster.
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35. Major Earthquakes in the World
•2011 TōhokuEarthquake and Tsunami (Japan)
•Magnitude: 9.1 (Mw)
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36. Major Earthquakes in the World
•1964 Great Alaska Earthquake (USA)
•Magnitude: 9.2 (Mw)
•Details: The strongest recorded earthquake in
North America, it caused significant damage in
Anchorage and generated tsunamis that affected
the Pacific coast.
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37. Major Earthquakes in the World
•1964 Great Alaska Earthquake (USA)
•Magnitude: 9.2 (Mw)
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38. Major Earthquakes in the World
•1906 San Francisco Earthquake (USA)
•Magnitude: 7.9 (Mw)
•Details: This earthquake caused widespread
destruction and fires in San Francisco, leading to
one of the worst natural disasters in U.S. history.
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39. Major Earthquakes in the World
•1906 San Francisco Earthquake (USA)
•Magnitude: 7.9 (Mw)
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40. Major Earthquakes in the Philippines
•1990 Luzon Earthquake
•Magnitude: 7.7 (Mw)
•Details: This earthquake caused extensive damage
in Northern and Central Luzon, leading to around
1,600 deaths and massive destruction in the city of
Baguio.
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41. Major Earthquakes in the Philippines
•1990 Luzon Earthquake
•Magnitude: 7.7 (Mw)
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42. Major Earthquakes in the Philippines
•2013 Bohol Earthquake
•Magnitude: 7.2 (Mw)
•Details: The earthquake struck the island of Bohol,
causing significant damage to infrastructure,
historical buildings, and leading to over 200 deaths.
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43. Major Earthquakes in the Philippines
•2013 Bohol Earthquake
•Magnitude: 7.2 (Mw)
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44. Major Earthquakes in the Philippines
•1976 Moro Gulf Earthquake
•Magnitude: 8.0 (Mw)
•Details: This powerful earthquake triggered a
tsunami that devastated coastal communities in the
southern Philippines, particularly in the Moro Gulf,
causing an estimated 5,000 to 8,000 deaths.
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45. Major Earthquakes in the Philippines
•1976 Moro Gulf Earthquake
•Magnitude: 8.0 (Mw)
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46. Major Earthquakes in the Philippines
•1863 Manila Earthquake
•Magnitude: Estimated 6.5–7.0
•Details: This earthquake caused widespread
destruction in Manila, including the collapse of
many buildings and churches, and resulted in
significant casualties.
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47. Major Earthquakes in the Philippines
•1863 Manila Earthquake
•Magnitude: Estimated 6.5–7.0
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48. Major Earthquakes in the Philippines
•1645 Luzon Earthquake
•Magnitude: Estimated 7.5 (Mw)
•Details: Known as the "San Andres" earthquake, it
caused extensive damage in Manila and
surrounding areas, including the collapse of many
Spanish-era structures.
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49. Major Earthquakes in the Philippines
•1645 Luzon Earthquake
•Magnitude: Estimated 7.5 (Mw)
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50. Causes of Earthquakes
•TECTONIC PLATE MOVEMENTS
•Convergent Boundaries: Where two tectonic plates
collide, leading to one plate being forced beneath
another, causing subduction-zone earthquakes (e.g., the
2004 Indian Ocean Earthquake).
•Divergent Boundaries: Where plates move apart,
creating tension that can cause earthquakes (e.g., along
mid-ocean ridges).
•Transform Boundaries: Where plates slide past each
other horizontally, generating strike-slip earthquakes
(e.g., the San Andreas Fault in California). 50

51. Causes of Earthquakes
•Volcanic Activity
•Earthquakes can occur in conjunction with volcanic
activity, often as a result of magma moving beneath
the Earth's surface (e.g., earthquakes associated
with the eruption of Mount St. Helens in 1980).
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52. Causes of Earthquakes
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53. Causes of Earthquakes
•Induced Seismicity
•Human activities, such as mining, reservoir-induced
seismicity (from the filling of large dams), and
hydraulic fracturing (fracking), can cause
earthquakes. These are typically smaller but can still
be significant in terms of local impact.
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54. Causes of Earthquakes
•Induced Seismicity
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55. Causes of Earthquakes
•Induced Seismicity
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56. Causes of Earthquakes
•Induced Seismicity
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57. Causes of Earthquakes
•Fault Slippage
•Stress accumulation along fault lines can cause a
sudden release of energy when the stress exceeds
the strength of rocks, resulting in an earthquake.
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58. Causes of Earthquakes
•Fault Slippage
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59. Causes of Earthquakes
•Isostatic Rebound
•The Earth's crust adjusts to the removal of surface
loads, such as the melting of glaciers, which can
lead to earthquakes.
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60. Causes of Earthquakes
•Isostatic Rebound
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61. Sources of Earthquake Data
•Global Seismographic Network (GSN)
•A worldwide network of seismographic stations
that monitor seismic activity. The data collected is
crucial for detecting, locating, and characterizing
earthquakes.
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62. Sources of Earthquake Data
•United States Geological Survey (USGS)
•Provides real-time earthquake data, maps, and
information on recent and historical seismic activity
worldwide through its Earthquake Hazards
Program.
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63. Sources of Earthquake Data
•Incorporated Research Institutions for Seismology
(IRIS)
•A consortium of universities and research
institutions that manage global seismic data and
provide resources for earthquake research and
education.
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64. Sources of Earthquake Data
•Philippine Institute of Volcanology and Seismology
(PHIVOLCS)
•The primary government agency responsible for
monitoring and studying earthquakes, volcanoes,
and tsunamis in the Philippines. They provide real-
time data, hazard maps, and information on local
seismic activity.
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65. Sources of Earthquake Data
•European-Mediterranean Seismological Centre
(EMSC)
•Provides rapid earthquake information and a
comprehensive database of seismic events,
focusing on the European-Mediterranean region.
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66. Sources of Earthquake Data
•Japan Meteorological Agency (JMA)
•Responsible for monitoring seismic activity in
Japan, the JMA provides detailed information on
earthquakes, including real-time alerts and
historical data.
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67. Sources of Earthquake Data
•Global Centroid Moment Tensor (CMT) Catalog
•Provides data on the moment tensor solutions for
earthquakes, which describe the characteristics of
seismic sources, helping researchers understand
earthquake mechanics.
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68. Sources of Earthquake Data
•International Seismological Centre (ISC)
•A non-profit organization that collects, archives,
and distributes seismic data from around the world,
providing a comprehensive catalog of global
seismicity.
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