p2 Geofisika Pertambangan Sifat Fisik Bumi

8/10/2019 p2 Geofisika Pertambangan Sifat Fisik Bumi

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Materi/Pokok BahasanI Pendahuluan (P.1)

II Sifat Fisika Bumi (P.2)

III Survey Geofisika (P.3)

IV Metode Gravitasi (P.4)

V Metode Geomagnet (P.5)

VI Metode Geolistrik (P.6-7)

VII Metode Seismik (P.8-10)

VIII Well Logg (P.11)

IX Georadar (P.12)

X Aplikasi Metode Geofisika padaPenambangan (P.13)

XI Aplikasi Metode Geofisika padaBencana Alam (P.14)

Universitas Bangka Belitung Jurusan Teknik Pertambangan

Lowrie (2007)




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Lowrie (2007)


Lowrie (2007)




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Simplified layered structure of the Earth’s interior

Lowrie (2007)




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Overview of Geophysical Techniques

Rocks and minerals in the earth vary in several ways.

These include:

• Density – mass per unit volume.• Magnetic susceptibility – the amount of magnetization in a

substance exposed t o a magnetic field.• Propagation velocity – the rate at which sound or seismic

waves are transmitted in the earth.• Resistivity and induced polarization – Resitivity is a

measure of the ability to conduct electricity and inducedpolarization is frequency-dependent variation in resistivity.

• Self-potential - ability to generate an electrical voltage.• Electromagnetic wave reflectivity and transmissivity –

reflection and transmission of electromagnetic radiation.

Gadallah & Fisher (2009)


Periodic table of the elements

Lutgens, et al. (2012)




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Reichard (2011)

Komposisi Bumi


Reichard (2011)

Komposisi Kerak Bumi




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ImportantNonsilicate

Minerals







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Composition of Igneous Rocks

Monroe & Wicander, 2009


Sedimentary rock




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Types of Igneous Rocks

GraniteDioriteGabbro

RhyoliteAndesiteBasalt Dacite

Granodiorite

Mafic Intermediate Felsic

F i n

e

C o a r s e

Setijadji (2011) - Slide


The P-wave shadow zone, caused

by refraction of P waves within the

Earth’s core.

The S-wave shadow zone. Because

no S waves pass through the core, the

core is apparently a liquid (or acts like

a liquid).

Carlson et al. (2011)

Geofisika Struktur Bumi




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The velocity of seismic P and S waves generally increases with depth

except in the low-velocity zone. The plastic asthenosphere slows down

seismic waves. Velocity increases at 400 and 670 kilometers may be

caused by mineral collapse.Carlson et al. (2011)





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Computation of half-rates of sea-floor spreading atdifferent spreading centers by measuring the

distances to anomalies with known radiometric ages

Lowrie (2007)


Comparison of the magnitudes of torques acting on

the 12 major lithospheric plates

Lowrie (2007)




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Average Densities of Common Rocks andSediments looked at in AS Geology


The Magnetic

Properties of

Some Common

Rock Types:




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Struktur Tubuh Bumi

Earth’s interior based on physical properties—the

lithosphere, asthenosphere, lower mantle, outer core,

and inner core.Lutgens, Tarbuck and Tasa (2012)


The rigid lithosphere includes the crust and uppermost mantle; it

forms the plates. The ductile asthenosphere acts as a lubricating

layer beneath the lithosphere. Oceanic lithosphere averages 70

kilometers thick; continental lithosphere varies from 125 to 250

kilometers thick.Carlson et al. (2011)




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Pangaea breakup and continental drift

Carlson et all. (2009)


The major plates of the world.

Carlson et al. (2009)




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The major and minor lithospheric plates

Lowrie (2007)


The present plate configurations and plate motions on Earth;

Frisch et all. (2011)




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Schematic model illustrating the three types of

plate margin

Lowrie (2007)


Hot Spots





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Earthquakes

Lutgens et al. (2012)


Locations of some of Earth’s major volcanoes

Monroe & Wicander (2009)




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Lutgens et al. (2012).


Map showing distribution of ages of oceanic crust. The oldest oceanic crust is of Jurassic age and is located in

the NW Pacifi c (ca. 185 Ma) and near the edges of the Central Atlantic (ca. 175 Ma). Small fragments of older

oceanic crust are captured between continental blocks in the Mediterranean Sea..

Mid-ocean ridges





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p2 Geofisika Pertambangan Sifat Fisik Bumi

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