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IntroductionSeismolo and the Earths Dee Interior

Seismologi dan Struktur Bumi

Minggu-ke Topik1 Pengantar Networks Seismisitas

2 Teori Elastisitas

3 Persamaan Gelombang Elastik

4 Quiz

5 Teori Sinar dan Tomografi Seismik

6 Gelombang Permukaan dan Osilasi Bebas

7 Struktur Bumi bagian dalam

8 Quiz

9 Sumber Seismik

10 Seismo-tectonik

11 Scattering Gel. Seismik

12 Quiz

13 TBA


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Literatur Text Books

Shearer, Introduction to Seismology, CambridgeUniversity Press, 1990.

Wysession and Stein, An introduction to seismology,earthquakes and earth structure, Blackwell Scientific

Kennett, The Seismic Wavefield, I+II, Cambridge

University Press

Lay and Wallace, Modern Global Seismology, AcademicPress, 1995.

Gubbins, Seismology and Plate Tectonics, Cambridge

University Press, 1990.

Aki and Richards, Quantitative Seismology, AcademicPress, 2002.

Anderson, Theory of the Earth, Blackwell, 1989.


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Introduction

Pengantar Seismologi

Seismolo and the Earths Dee Interior


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Sebuah seismogram


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Seismologi dan Struktur Bumi

Sejarah Singkat Seismologi

Todays seismicity (live!)SeismometriJejaring Seismik

Gempabumi yang terjadi seduniaDistribusi gempabumiGempa Utama Abad iniSumber gempaKuantifikasi gempa

Struktur Bumi

Struktur secara Spherically symmetricModel 3-D (tomografi seismik)

10 Tantangan Seismologi


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History The first seismometer

Seismometer Chang Heng (132 M)

Dengan alat iniarah sumber

gempa apat diprediksi !


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History milestones

Di Eropa riset di bidang seismologi berkembangsemenjak kejadian 2 gempa merusak pada abadke 18, yaitu:

1755 gempabumi Lissabon, Portugal, 32000 tewasgempabumi di Calabria, Italy30000 tewas

Experimental seismology Theoretical seismology

1846 Mallet

1880 Milne (first real seismograph)1889 First teleseismic recording

(Potsdam)

1884 Intensity scale (Rossi-Forrel)

1831 Poisson, gelombang pada

medium infinit1849 Stokes, Gel. P dan S sebagai

dilatasi dan gel. shear

1885 Rayleigh, Gel pada mediumsetengah tak hingga, gel. Permukaan


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History milestones (contd)

1900 Oldham: identification of P, S, and surfacewaves

1901 Wiechert: first geophysical institute inGttingen, Germany. Development ofseismometers

1903 Foundation of International SeismologicalAssociation

1906 San Francisco earthquake: 1000 killed.

Galitzin seismograph

1909 Mohorovicic discontinuity (MOHO)

1911 Theory of Love waves

Seismological Society of America


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History milestones (contd)

1913 Determination of radius of Earths core

by Benno Gutenberg (Gttingen)

1923 Tokyo earthquake (Great Japanese Quake)

250000 killed, Foundation of Earthquake ResearchInstitute (ERI)

1903 Foundation of International SeismologicalAssociation

1931

1932

Benioff Seismometer

Strain seismometer

19351936 Richter magnitudeDiscovery of the Earths inner core by IngeLehmann (1888-1993)

1940 Sir Harrold Jeffreys, Cambridge

Traveltime tables. Bullen density model



History milestones (after 1950)

1960 Pengamatan osilasi bebas Bumi pasca gempa

besar di Chile 1960

1963 Limited Test Ban Treaty, World WideStandard Seismograph Network (WWSSN)

Late

60s

Konsep tektonik lempeng diakui

1981 Preliminary Reference Earth Model (PREM)

Mid 80s Model tomografi 3-D pertama yang

menunjukan heterogenitas mantel bumi

1997 Rotasi dari inti bumi bagian dalam



Monitoring Seismik di Jerman (Sta-FFB)

Rekaman gempabumi selama 24 jamdi Observatorium FFB



Seismometer di Indonesia

Distribution seismometers diIndonesia yang dioperasikan

oleh BMKG



Gempabumi di Dunia

distribusi gempa sejak 1954-1998 dengan magnitudo >= 4.0NEIC (National Earthquake Information Center)ada lebih dari 240 000 seismic events with magnitude >=4.0

BGR Hannover



Gempabumi di Indonesia



Gempabumi di Jerman

Earthquakes in Germany

(historical and measured)(BGR Hannover)



Statistika Gempabumi

MS Earthquakesper year

---------- -----------8.5 - 8.9 0.38.0 - 8.4 1.17.5 - 7.9 3.17.0 - 7.4 156.5 - 6.9 56

6.0 - 6.4 210



The Earthquake - Top Ten Chart

2.) Sumatra-Andaman 26/12/2004 9.3 Mw

3.) Alaska 03/28/1964 9.2 Mw 61.1 N 147.5 W

4.) Russia 11/04/1952 9.0 Mw 52.75 N 159.5 ETohuku 11/03/2011 8,9 Mw Tsunami

5.) Ecuador 01/31/1906 8.8 Mw 1.0 N 81.5 W

6.) Alaska 03/09/1957 8.8 Mw 51.3 N 175.8 W

7.) Kuril Islands 11/06/1958 8.7 Mw 44.4 N 148.6 E

8.) Alaska 02/04/1965 8.7 Mw 51.3 N 178.6 E

9.) India 08/15/1950 8.6 Mw 28.5 N 96.5 E

10.) Argentina 11/11/1922 8.5 Mw 28.5 S 70.0 W

1.) Chile 05/22/1960 9.5 Mw 38.2 S 72.6 W

and the winner is



Gempabumi - Top Ten - Map

The ten largest earthquakes this century



Seismologi dan Tektonik Lempeng

Tectonic plates on Earth



Rekonstruksi gerakan lempeng



Konsep Tektonik Lempeng



Tektonik Lempeng Mantle Convection

A current issue of debate is whether the Earths mantle convectsas a whole or whether there is layered convection.

Seismology can only provide the present state of the Earthsconvective system!



Tektonik Lempeng hot spots

Schematic pictureof the Hawaiian islandchain and the underlying

Hot spot.

The origin of hot spots and their mechanism are still poorly understood.



Plate Tectonics hot spots - plumes



Tektonik Mid-oceanic ridges

Global ridge system Topography mid-atlantic ridge

Plate motions are up to 15cm per year



Plate Tectonics Discovery

The proof of plate tectonics came from the magnetization ofthe seafloor as a function of distance from the ridge axes.



Plate Tectonics Volcanoes

Pinatubo, 1991 Mount St. Helens, 1980


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Plate Tectonics Volcanoes (contd)


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Plate Tectonics Fault Zones

San Andreas Fault Fault zones in California


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Fault zone waves

Considerable FZtrapped waveenergy generated.

Receivers

l d h


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Fault zone structure at depth

New interpretation Previous concept

Shallow LVfeatures

LV featuresextending togreater depth


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Plate Tectonics Earthquakes

Earthquake damage in California


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Plate Tectonics Earthquakes

Seismologist recordingaftershocks in California


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Earthquake sources


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Mercalli Intensity and Richter MagnitudeMagnitudo Intensitas Diskripsi

1.0-3.0 I I. Tidak dirasakan kecuali oleh orang-orang pada kondisi khusus.

3.0 - 3.9 II - III II. Dirasakan oleh orang yang sedang tiduran, terutama di lantai bangunan.III. Felt quite noticeably by persons indoors, especially on upper floors of buildings.Many people do not recognize it as an earthquake. Standing motor cars may rockslightly. Vibrations similar to the passing of a truck. Duration estimated.

4.0 - 4.9 IV - V IV. Felt indoors by many, outdoors by few during the day. At night, some awakened.Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truckstriking building. Standing motor cars rocked noticeably.V. Felt by nearly everyone; many awakened. Some dishes, windows broken. Unstableobjects overturned. Pendulum clocks may stop.

5.0 - 5.9 VI - VII VI. Felt by all, many frightened. Some heavy furniture moved; a few instances offallen plaster. Damage slight.VII. Damage negligible in buildings of good design and construction; slight to moderatein well-built ordinary structures; considerable damage in poorly built or badly designedstructures; some chimneys broken.

6.0 - 6.9 VII - IX VIII. Damage slight in specially designed structures; considerable damage in ordinarysubstantial buildings with partial collapse. Damage great in poorly built structures. Fall

of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned.IX. Damage considerable in specially designed structures; well-designed framestructures thrown out of plumb. Damage great in substantial buildings, with partialcollapse. Buildings shifted off foundations.

7.0 andhigher

VIII orhigher

X. Some well-built wooden structures destroyed; most masonry and frame structuresdestroyed with foundations. Rails bent.XI. Few, if any (masonry) structures remain standing. Bridges destroyed. Rails bentgreatly.XII. Damage total. Lines of sight and level are distorted. Objects thrown into the air.


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The Earths Deep Interior


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The Earths Radial Structure


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Traveltimes of Teleseismic Phases

The Earths deep structure isdetermined by inverting thousands ofseismic travel times

-> seismic tomography


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3-D tomography

Maybe the mostimportant goal in

global seismology todayis to determinethe Earths global 3-Dstructure withhigh resolution- Source: Harvard

l h ll


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Seismology Schematically

Seismic Source

Ruptures, crack propagation,physics of earthquakes,

magnitude, faulting, seismiccreep, radiation pattern,Earthquake precursors,

aftershocks, fault planes, etc.

Propagation Effects

heterogeneities, scattering, attenuation,anisotropy, rays, body waves, surface waves,

free oscillations, reflections, refractions,trapped waves, geometrical spreading, etc.

Seismometer

Filtering, (de)convolution, threecomponents, spectrum, broadband,

strong-motion, tilt, long-period,amplification, etc.

h ll l


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Introduction

Grand Challenges in Seismology


H d f l l


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Introduction

How do fault slips?



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Wiechert Pendulum seismometer


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Wiechert Pendulum seismometer

The 1000 kg Wiechert invertedpendulum seismograph (after Wiechert,

1904). The plate P is attached to theframe of the instrument. N is attachedto the pendulum mass. The motion ofthe mass relative to the frame isresolved at A into perpendicularcomponents. Restoring force is appliedto the mass M from springs at C, C', bymeans of the rods B, B'. H, H' are thedamping cylinders. The whole invertedpendulum is pivoted at K. In the actualseismometer, the rotation of thependulum about K takes place in flatsprings, which are arranged in a Cardanhinge to permit the pendulum to move inany horizontal direction.

Back to the listModern seismometers

Modern 3 C seismometer


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Modern 3-C seismometer

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1889 The first teleseismic record


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1889 - The first teleseismic record

This seismogram wasrecorded in Potsdam in1889. The seismicwaves were generatedby an earthquake inJapan.

Back to the list

Benno Gutenberg


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Benno Gutenberg

Back to list

Charles Richter


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Charles Richter

Back to list

Sir Harold Jeffreys


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Sir Harold Jeffreys

Back to list

1891-1989

Nuclear Explosions until Today


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Nuclear Explosions until Today

Back to list BGR Hannover

Alaska 1964 earthquake


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Alaska 1964 earthquake

Back to list

San Francisco earthquake in FFB#


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San Francisco earthquake in FFB#

Back to the list

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