Plate Tectonics - Blog FTSL

SISTEM ALAM
SEMESTA
Titi
Arneth
Arlene
Aaron
Zadrach
Plate Tectonics: A Unifying
View of Earth
Komposisi Bumi
•Kerak
•Mantel
•Inti
Dimention 8
Kerak Bumi
-Kerak benua :
ketebalan mencapai 100 km
komposisi granitis; Si & Al
bersifat getas
berat jenis lebih kecil.
-Kerak samudera :
ketebalan : 8-10km
komposisi : basaltis;Si & Mg
bersifat lentur, lebih berat.
Oceanic Crust
Konsep Dasar Tektonik Lempeng
Dua jenis kerak : Kerak Benua (Si - Al) dan
(Si - Ma)
Kerak Samudera
Bagian luar dari kulit bumi secara fisik dapat dibagi menjadi
Litosfir dan Astenosfir
Litosfir terdiri dari kerak dan mantel atas bagian atas
Secara umum, litosfir bersifat getas (brittle) dengan
ketebalan rata-rata 100 km
Astenosfir adalah mantel bagian atas yang lunak dan
bersifat lentur (ductile) , dapat mencapai sampai
kedalaman 700 km
Generation 4.6
The Convecting Mantle
• Mantle convection
– Motion driven by Earth’s interior heat energy
• Sources of energy
– Gravitational potential energy
– Decay of radioactive elements
• Movement
– Heat moves to cooler regions
– Convection cells in mantle
– Very slow
• 200 million years for one cycle
Batas Lempeng
A.Divergen
B. Konvergen
A
C. Transform
B
C
Motion 12.1
Divergen
• Ciri-ciri :
– Gunungapi
• Rangkaian pegunungan
– Gempa bumi
• Pemekaran samudera
- Lempeng-lempeng
bergerak saling menjauhi
- Ada punggung tengah samudera
(pusat pemekaran purba)
- MuncuL pusat-pusat pemekaran baru
Konvergen
• Beberapa tipe :
– Samudera – samudera
• Lajur subduksi
– Palung laut dalam
– Busur Kepulauan
– Benua – benua
• Rangkaian pegunungan
yg tinggi,berkelok-kelok
– Benua – samudera
• Lajur subduksi
– Palung laut dalam
– Busur gunung api
Transform
• Dua lempeng saling
berpapasan;bergeser satu sama
yang lain
– Gempabumi sebagai hasil pergerakan ini
Batas Lempeng
• 3 Tipe
– Divergen
– Konvergen
– Transform
Motion 12.9
Peta lempeng- lempeng tektonik
“BERTEMU”
(subduksi)
MEMISAH DIRI
Peta Interaksi Lempeng
BERPAPASAN
Mengenal Gerak Relatif Lempeng
Paleomagnetisme
Volkanisme
Pengukuran geodetik (GPS)
Studi mekanisme fokus gempa
PALEOMAGNETISME
PEMBALIKAN MEDAN MAGNIT SEJALAN
DENGAN PERUBAHAN EVOLUSI BUMI
Magnet 12.3
Volkanisme
hotspot : lempeng bergerak, sumber tetap.
Rangkaian gunung api
Hotspot 1.2
Corr 12.2
Volkan 12.1.2
Global Plate Motion from GPS
Seismisitas (Seismicity)
Seismisitas Australia, Indonesia dan New Zealand
gempa 12.1.2
Quiz
•Jelaskan secara singkat (lengkapi
dengan gambar) mekanisme batas
lempeng
• Jelaskan secara singkat
bagaimana cara mengetahui/
mempelajari pergerakan kerak bumi
• Buatlah sketsa struktur dan
komposisi bumi (lengkapi dengan
notasi
Definition
• Positioning is a process of defining
spatial relation of an object with
respect to another object or
reference by distance (horizontal or
vertical and angle)
Q
P
SPQ
Reference
• In 2-dimensional space, position of
an object is usually referred to
Cartesian coordinate system
• P is located
y
in xP and yP
P (xP,yP)
yP
xP
x
Position on Earth
• Position of an object on Earth is
expressed in geographic coordinate
Satellite Positioning
• Modern technique in positioning
employs Global Positioning System
(GPS) satellite
GPS Receivers
• Users receive position data anytime
and anywhere on a GPS receiver
• Performance of GPS receivers range
from simple handheld gadgets to
geodetic types
Positioning Application
• Navigation:
– Aircraft, marine vessel, land traffic, etc.
• Survey:
– Field sampling, etc.
• Mapping:
– Road, river, parcel
boundary, etc.
• Monitoring:
– Plate movement,
land slide, etc.
Global Positioning System (GPS)
Jaringan GPS
Copyright: [email protected]
Global Plate Motion from GPS
Regional Motion from GPS
Malaysia (MASS) :18, Thailand (Game-T) :3,
Indonesia (Sugar+FORSGC+IGS) : 11, ITB-Nagoya :1
Total continue:33 and 4 newly constructed GPS by Nagoya Univ.
Time : 2004-2006
Regional Motion from GPS
Copyright: [email protected]
Regional Motion from GPS
Interseismic deformation can not be explained only by full
coupling of Indo-Austria and Sunda block.
More source(s) are needed
Regional Motion from GPS
Probability of earthquake occurrence
versus GPS Observation
Strain
Critical stress
Stress drop
(~1MPa)
Stress build-up
(~30 Pa/day or ~10 kPa/yr)
time
Recurrence interval
(~100 yr)
Horizontal displacement due to
the 2004 Sumatra Eq
Horizontal displacement due to the 2009
Manokwari Earthquake