module 13 earthquake
DESCRIPTION
bahan ajalar Geologi Dasar Fakultas Teknologi Mineral UPN "Veteran" YogyakartaTRANSCRIPT
![Page 1: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/1.jpg)
Module 13Module 13
EarthquakeEarthquake
![Page 2: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/2.jpg)
Photo credit: USGS
EARTHQUAKEEARTHQUAKE
![Page 3: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/3.jpg)
EARTHQUAKEEARTHQUAKE
EarthquakeEarthquake A series of shock waves generated at a point (A series of shock waves generated at a point (the the
focusfocus) within the Earth”s crust or mantle) within the Earth”s crust or mantle The point on the surface of the Earth above the The point on the surface of the Earth above the
focus is called the focus is called the epicenterepicenter Three main types of wave motion are generated Three main types of wave motion are generated
by an earthquake: P-Waves; S-Waves; dan L-by an earthquake: P-Waves; S-Waves; dan L-WavesWaves
![Page 4: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/4.jpg)
EARTHQUAKEEARTHQUAKE
P-WavesP-Waves• High-frequencyHigh-frequency• Short-wavelengthShort-wavelength• Longitudinal wavesLongitudinal waves• Can be reflected andCan be reflected and
refracted refracted • Travel through theTravel through the
solid and the liquidsolid and the liquidpart of the Earthpart of the Earth
S-WavesS-Waves• High-frequencyHigh-frequency• Short-wavelengthShort-wavelength• Transverse wavesTransverse waves• Can be reflected andCan be reflected and
refractedrefracted• Travel through theTravel through the
solid part of the solid part of the Earth at varyingEarth at varyingvelocities.velocities.
• Propagated in allPropagated in alldirections fromdirections fromthe focusthe focus
L-WavesL-Waves• Low-frequencyLow-frequency• Long-wavelengthLong-wavelength• Transverse vibrationsTransverse vibrations• Confined to the outerConfined to the outer
skin of the crustskin of the crust• Responsible for most Responsible for most
of the destructiveof the destructiveforce of earthquakeforce of earthquake
![Page 5: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/5.jpg)
Body WavesBody Waves Primary or Primary or CompressionalCompressional Secondary or ShearSecondary or Shear
Surface WavesSurface Waves Rayleigh (large vertical displacements)Rayleigh (large vertical displacements) Love (shear)Love (shear)
EARTHQUAKEEARTHQUAKESeismic Wave TypesSeismic Wave Types
![Page 6: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/6.jpg)
Seismic Wave TypesSeismic Wave Types
Bo
dy
Wa
ves
Bo
dy
Wa
ves
Su
rfa
ce W
ave
sS
urf
ace
Wav
es
EARTHQUAKEEARTHQUAKE
Primary (P) WavePrimary (P) Wave Secondary (S) WaveSecondary (S) Wave
Love WaveLove Wave Rayleigh WaveRayleigh Wave
![Page 7: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/7.jpg)
3 m offset
1906 San Francisco Earthquake1906 San Francisco Earthquake
Elastic Rebound TheoryElastic Rebound TheoryEARTHQUAKEEARTHQUAKE
![Page 8: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/8.jpg)
Offset Lettuce Rows - El Centro, CAOffset Lettuce Rows - El Centro, CA
Elastic Rebound TheoryElastic Rebound TheoryEARTHQUAKEEARTHQUAKE
Where does the offset occur?Draw the relative movement
![Page 9: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/9.jpg)
Vp = k + 4/3µ
1/2 density
µ shear modulus (rigidity)
k bulk modulus (rigidity)
Vs = µ
1/2
because shear modulus (rigidity) for fluid is zero,S waves cannot propagate through a fluid
consequence of equations is that P waves are 1.7x faster than S
can infer physical properties from P and S waves
Equations for velocitiesEquations for velocitiesEARTHQUAKEEARTHQUAKE
![Page 10: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/10.jpg)
Pancaked BuildingPancaked Building - 1985 Mexico City - 1985 Mexico City
Earthquakes don’t kill people - buildings do!
Effects of the EarthquakeEffects of the Earthquake
![Page 11: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/11.jpg)
Soil Liquefaction - 1964 NiSoil Liquefaction - 1964 Niiigata, Japangata, Japan
Effects of the EarthquakeEffects of the Earthquake
![Page 12: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/12.jpg)
Surface Displacement - 1964 AlaskaSurface Displacement - 1964 Alaska
Effects of the EarthquakeEffects of the Earthquake
![Page 13: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/13.jpg)
Ground Rupture, 1906 Olema, CAGround Rupture, 1906 Olema, CA
Effects of the EarthquakeEffects of the Earthquake
![Page 14: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/14.jpg)
Fence Compression - Gallatin County, MTFence Compression - Gallatin County, MT
Effects of the EarthquakeEffects of the Earthquake
![Page 15: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/15.jpg)
Buckled Concrete - 1971 San Fernando, CABuckled Concrete - 1971 San Fernando, CA
Effects of the EarthquakeEffects of the Earthquake
![Page 16: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/16.jpg)
Tsunami Devastation - 1964 Alaska EarthquakeTsunami Devastation - 1964 Alaska Earthquake
Effects of the EarthquakeEffects of the Earthquake
![Page 17: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/17.jpg)
TsuTsunnaammi Generationi Generation
Effects of the EarthquakeEffects of the Earthquake
![Page 18: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/18.jpg)
Tsunami Wave Propagation TimesTsunami Wave Propagation Times
Effects of the EarthquakeEffects of the Earthquake
![Page 19: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/19.jpg)
Vertical Component SeismometerVertical Component Seismometer
Locating the EarthquakeLocating the Earthquake
![Page 20: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/20.jpg)
Horizontal Component SeismometerHorizontal Component Seismometer
Locating the EarthquakeLocating the Earthquake
![Page 21: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/21.jpg)
First Arrivals – Seismographic RecordFirst Arrivals – Seismographic Record
Locating the EarthquakeLocating the Earthquake
![Page 22: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/22.jpg)
Distance – Time RalationsDistance – Time Ralations
Locating the EarthquakeLocating the Earthquake
![Page 23: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/23.jpg)
P P vsvs S Wave Travel Time Curves S Wave Travel Time Curves
Locating the EarthquakeLocating the Earthquake
![Page 24: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/24.jpg)
Earthquake Location by RangeEarthquake Location by Range
Locating the EarthquakeLocating the Earthquake
![Page 25: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/25.jpg)
• Three distinct methods to measure earthquakes. Two Three distinct methods to measure earthquakes. Two based on energy and one based on intensity.based on energy and one based on intensity.– Richter Magnitude Scale: originally developed for Richter Magnitude Scale: originally developed for
southern California. Log scale, which has no upper southern California. Log scale, which has no upper bound. Small earthquakes may yield negative bound. Small earthquakes may yield negative values. Tends to be inaccurate at >7 magnitudes.values. Tends to be inaccurate at >7 magnitudes.
– Moment Magnitude Scale: measurement of the Moment Magnitude Scale: measurement of the amount of work done during the earthquake. Based amount of work done during the earthquake. Based on rock strength, area of rupture, and displacement on rock strength, area of rupture, and displacement during event.during event.
– Modified Mercalli Intensity Scale: based on the Modified Mercalli Intensity Scale: based on the damage associated with a particular event at a damage associated with a particular event at a particular location. Ranges from I (less damage) to particular location. Ranges from I (less damage) to XII (more damage). XII (more damage).
Measuring the EarthquakeMeasuring the Earthquake
![Page 26: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/26.jpg)
Magnitude-Description-Intensity-Frequency RelationsMagnitude-Description-Intensity-Frequency RelationsMeasuring the EarthquakeMeasuring the Earthquake
![Page 27: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/27.jpg)
1886 Charleston, SC earthquake
Measuring the EarthquakeMeasuring the EarthquakeModified Modified Mercalli Mercalli Intensity Index (1931)Intensity Index (1931)
![Page 28: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/28.jpg)
Measuring the EarthquakeMeasuring the EarthquakeHistorical Earthquake MagnitudesHistorical Earthquake Magnitudes
![Page 29: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/29.jpg)
• Earthquakes at Plate Boundaries
• Subduction Angle
Earthquake and Plate TectonicsEarthquake and Plate Tectonics
![Page 30: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/30.jpg)
Earthquake DistributionEarthquake DistributionEarthquake and Plate TectonicsEarthquake and Plate Tectonics
![Page 31: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/31.jpg)
Relative plate motion and boundariesRelative plate motion and boundariesEarthquake and Plate TectonicsEarthquake and Plate Tectonics
![Page 32: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/32.jpg)
different types of structures are associated with each boundary type:divergent/rifting: extensional (normal faulting)convergent/collisional: compressional (thrust faulting)transform/transcurrent: shear-dominated (strike-slip faulting)
Earthquake and Plate TectonicsEarthquake and Plate Tectonics
![Page 33: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/33.jpg)
Divergent Boundary and EarthquakesDivergent Boundary and EarthquakesEarthquake and Plate TectonicsEarthquake and Plate Tectonics
![Page 34: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/34.jpg)
EEarthquakes alongarthquakes alongmid-ocean ridge aremid-ocean ridge areshallower than thoseshallower than thosealong subduction zonealong subduction zone
from: http://www.pmel.noaa.gov/vents/coax/coax.html
Divergent Boundary and EarthquakesDivergent Boundary and EarthquakesEarthquake and Plate TectonicsEarthquake and Plate Tectonics
![Page 35: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/35.jpg)
Earthquake and Plate TectonicsEarthquake and Plate TectonicsTransform Boundary and EarthquakesTransform Boundary and Earthquakes
![Page 36: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/36.jpg)
The western USThe western USis somewhat is somewhat anomalousanomalousNote: absence ofNote: absence ofdeep earthquakesdeep earthquakes
from: http://www.pmel.noaa.gov/vents/coax/coax.html
Earthquake and Plate TectonicsEarthquake and Plate TectonicsTransform Boundary and EarthquakesTransform Boundary and Earthquakes
![Page 37: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/37.jpg)
Earthquake and Plate TectonicsEarthquake and Plate TectonicsConvergent Boundary and EarthquakesConvergent Boundary and Earthquakes
![Page 38: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/38.jpg)
Shallow vs. Deep Subduction EarthquakesShallow vs. Deep Subduction Earthquakes
Continent-continent collisionContinent-continent collisionzones have broad areas of zones have broad areas of of relatively shallow seismicityof relatively shallow seismicity
Ocean-continent convergentOcean-continent convergentmargins have earthquakes focimargins have earthquakes focithat extend to great depths.that extend to great depths.Mechanism tend to change fromMechanism tend to change fromextension to compression extension to compression downdip.downdip.
Earthquake and Plate TectonicsEarthquake and Plate Tectonics
![Page 39: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/39.jpg)
deep intermediate shallow
• Epicenters: Epicenters: location of earthquake rupture projected to location of earthquake rupture projected to surface;surface;
• DDip of slab leads to observed seismicity patterns:ip of slab leads to observed seismicity patterns: deeper deeper farther from trenchfarther from trench
• LLocation of downgoing slab as it dives into mantleocation of downgoing slab as it dives into mantle i is defined s defined by seismicityby seismicity..
• EEarthquakes occur alongarthquakes occur along an inclined belt:an inclined belt: the Wadati-Benioff the Wadati-Benioff zonezone r reaches maximum depth of ~670 kmeaches maximum depth of ~670 km
from: http://www.geo.lsa.umich.edu/~crlb/COURSES/270
Earthquake and Plate TectonicsEarthquake and Plate Tectonics
![Page 40: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/40.jpg)
SSeismicity of subduction zoneseismicity of subduction zones
all from: http://www.pmel.noaa.gov/vents/coax/coax.html
Earthquake and Plate TectonicsEarthquake and Plate Tectonics
Seismicity of Japan and Kuril Island:Seismicity of Japan and Kuril Island:1975 - 19951975 - 1995
Seismicity Fiji IslandsSeismicity Fiji IslandsRegion: 1977 - 1997Region: 1977 - 1997
Seismicity of Peru-BoliviaSeismicity of Peru-BoliviaBorder Region: 1977 - 1997Border Region: 1977 - 1997
![Page 41: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/41.jpg)
slab is cold and thus can haveslab is cold and thus can have earthquakes at greater depthsearthquakes at greater depths
Tomography (3D seismic)Tomography (3D seismic)
note continuity of blue slabnote continuity of blue slab to depths on order of 670 kmto depths on order of 670 km
blue is fast…blue is fast… interpreted as slabinterpreted as slab
from: http://www.pmel.noaa.gov/vents/coax/coax.html
Earthquake and Plate TectonicsEarthquake and Plate Tectonics
![Page 42: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/42.jpg)
SSeismicity along subduction zones:eismicity along subduction zones: earthquakes are shallow, intermediate, and deepearthquakes are shallow, intermediate, and deep but have systematic locationbut have systematic location related to subducting slarelated to subducting slabb shallow adjacent to trench and deep farthest awayshallow adjacent to trench and deep farthest away
from: http://www.geo.lsa.umich.edu/~crlb/COURSES/270
Earthquake and Plate TectonicsEarthquake and Plate Tectonics
![Page 43: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/43.jpg)
Tsunami Hazard Area Map of IndonesiaTsunami Hazard Area Map of Indonesia
![Page 44: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/44.jpg)
Earthquake Hazard Area Map of IndonesiaEarthquake Hazard Area Map of Indonesia
![Page 45: Module 13 earthquake](https://reader035.vdocuments.us/reader035/viewer/2022062512/554a35dcb4c90526578b579e/html5/thumbnails/45.jpg)
Map of Distribution of Active Faults and Map of Distribution of Active Faults and Destroying Earthquake Epicenters of IndonesiaDestroying Earthquake Epicenters of Indonesia