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LAND SUBSIDENCE CHARACTERISTICS OF BANDUNG BASIN (INDONESIA) BETWEEN 2000 AND 2005
AS ESTIMATED FROM GPS SURVEYS
HASANUDDIN Z. ABIDIN,HERI ANDREAS, M. GAMAL, D. DARMAWAN
Geodesy Research Division,Faculty of Civil and Environmental EngineeringBandung Institute of Technology, INDONESIA,
• subsidence due to groundwater extraction, • subsidence induced by the load of constructions
(i.e. settlement of high compressibility soil), • subsidence caused by natural consolidation of alluvium soil, and • geotectonic subsidence.
Types of Subsidence :Land Subsidence
In Indonesia, land subsidence of urban coastal areasare usually caused by excessive groundwater extraction.
The already observed subsidence areas :Jakarta, Semarang and Bandung
The expected subsidence areasDenpasar, Surabaya and Medan
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia
Land Subsidence in Indonesian Cities
Denpasar
Cilegon
Denpasar
Cilegon
• Jakarta• Bandung• Semarang
• Surabaya• Denpasar• Cilegon• Medan
Observed land subsidence : Expected land subsidence :
observed decrease in groundwater level
BandungBandungWest JavaWest JavaIndonesiaIndonesia
Bandung
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia
Bandung is the capital of West Java Province and has a population about of 2.5 million (1995).It is surrounded by several medium sized towns which formed the Greater Bandung, and hasa total population of about 3.5 million.
The Greater Bandung lies in the catchment area of the upper Citarum river and is surrounded by range of hills and volcanoes: some of which are still active, formed the inter-montane basin, and has an area of about 2250 km2.
The central part of the basin, where most of which occupied by urban and industrial areas, is a plain measuring about 40 km East-West and about 30 km North-South
Bandung Basin Java Island
Ref. : Soetrisno, 1996
Http://www.bandungcity.homepage.com/
Bandung
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia
Bandung Basin
Ref: [Dam et al., 1996]
Structural Setting of Bandung Basin
Bandung
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia
INITIAL AIMS OF STUDYINITIAL AIMS OF STUDY
• IS LAND SUBSIDENCE A REAL PHENOMENON IN BANDUNG ?• IF YES, WHY LAND SUBSIDENCE IS HAPPENING ? • HOW IS THE MECHANISM OF LAND SUBSIDENCE ?
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia
Spatialplanning
Infrastructuredesign and
constructionFlood
control
Groundwaterextractionregulation
Environmentalconservation
IMPORTANCE OFLAND SUBSIDENCE INFORMATION IN BANDUNG
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia
PRINCIPLE OF LAND SUBSIDENCE MONITORINGUSING REPEATED GPS SURVEY METHOD
Coordinates from Survey # 1Coordinates from Survey # 2
GPS networkCovering the study area
GPS satellites
LANDSUBSIDENCE
HEIGHTDIFFERENCES
LAND SUBSIDENCECHARACTERISTICS
Modeling
Statistical andGeometrical
Testings
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia
GPS NETWORK FOR MONITORINGLAND SUBSIDENCE in BANDUNG BASIN
GPS PointsGPS Reference Point
SagulingDam
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
RCK1
BNJR
CMHI
MJL2KPO2
KPO1BRGA
CPRY
BM9L
BM13L
BM18L
BM19L BM30LBM30X
BANDUNG BASIN
10 km
SagulingDam
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
RCK1
BNJR
CMHI
MJL2KPO2
KPO1BRGA
CPRY
BM9L
BM13L
BM18L
BM19L BM30LBM30X
BANDUNG BASIN
NORTHSurvey-1 : 21-24 Feb. 2000Survey-2 : 21-30 Nov. 2001Survey-3 : 11-14 July 2002Survey-4 : 1-3 June 2003Survey-5 : 24-27 June 2005
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia
GPS NETWORK FOR MONITORINGLAND SUBSIDENCE in BANDUNG BASIN
SOME GPS POINTS IN BANDUNG
PSCA
KOPO1
CMHI
MJLY2
B30X
BNJR
UJBR
RCK1
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia
0
0.5
1
1.5
2
2.5
3
3.5
Observed GPS stations (5 surveys)
Survey-2 up to Survey-5
Survey-1 Standar deviation (cm) ofrelative ellipsoidal height
Stan
dard
dev
iati
on (
cm)
0
0.5
1
1.5
2
2.5
3
3.5
Observed GPS stations (5 surveys)
Survey-2 up to Survey-5
Survey-1 Standar deviation (cm) ofrelative ellipsoidal height
0
0.5
1
1.5
2
2.5
3
3.5
Observed GPS stations (5 surveys)
Survey-2 up to Survey-5
Survey-1 Standar deviation (cm) ofrelative ellipsoidal height
Stan
dard
dev
iati
on (
cm)
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia
GPS receiver : dual-frequency geodetic-typeSession length : in general 10 to 12 hoursData rate : 30 seconds, Mask angle : 15o
Processing : SKIPro, precise ephemeris, Saastamoinen tropospheric model, ionospheric free linear combination after fixing the integer ambiguities of L1 and L2 signals
GPS SURVEYS IN BANDUNG
SagulingDam
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
RCK1
BNJR
CMHI
BRGA
BM9L
BM13L
BM18L
BM19L
BANDUNG BASIN
NORTH
SagulingDam
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
RCK1
BNJR
CMHI
BRGA
BM9L
BM13L
BM18L
BM19L
BANDUNG BASIN
SagulingDam
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
RCK1
BNJR
CMHI
BRGA
BM9L
BM13L
BM18L
BM19L
BANDUNG BASIN
NORTH
SagulingDam
-6.7
-15.7
-7.7
Fixed
-15.0
-2.6
-10.0
-7.7
-19.0
BANDUNG BASIN
10 km
Feb.2000 – Nov.2001
SagulingDam
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
RCK1
BNJR
CMHI
BRGA
BM9L
BM13L
BM18L
BM19L
BANDUNG BASIN
NORTH
SagulingDam
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
RCK1
BNJR
CMHI
BRGA
BM9L
BM13L
BM18L
BM19L
BANDUNG BASIN
SagulingDam
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
RCK1
BNJR
CMHI
BRGA
BM9L
BM13L
BM18L
BM19L
BANDUNG BASIN
NORTH
SagulingDam
-6.7
-15.7
-7.7
Fixed
-15.0
-2.6
-10.0
-7.7
-19.0
BANDUNG BASIN
10 km
Feb.2000 – Nov.2001
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
RCK1
BNJR
CMHI
KPO2
KPO1BRGA
CPRY
BM9L
BM13L
BM30L
BANDUNG BASIN
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
RCK1
BNJR
CMHI
KPO2
KPO1BRGA
CPRY
BM9L
BM13L
BM30L
BANDUNG BASIN
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
RCK1
BNJR
CMHI
KPO2
KPO1BRGA
CPRY
BM9L
BM13L
BM30L
BANDUNG BASIN
-2.4
-17.2
-4.0-1.1
Fixed
-14.0
-1.6
-5.1
-3.6
-16.7
-0.1
-11.2
-2.8
BANDUNG BASIN
SagulingDam
NORTH NORTH
10 km
Nov.2001 – July 2002
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
RCK1
BNJR
CMHI
KPO2
KPO1BRGA
CPRY
BM9L
BM13L
BM30L
BANDUNG BASIN
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
RCK1
BNJR
CMHI
KPO2
KPO1BRGA
CPRY
BM9L
BM13L
BM30L
BANDUNG BASIN
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
RCK1
BNJR
CMHI
KPO2
KPO1BRGA
CPRY
BM9L
BM13L
BM30L
BANDUNG BASIN
-2.4
-17.2
-4.0-1.1
Fixed
-14.0
-1.6
-5.1
-3.6
-16.7
-0.1
-11.2
-2.8
BANDUNG BASIN
SagulingDam
NORTH NORTH
10 km
NORTH NORTH
10 km
Nov.2001 – July 2002
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
BNJR
CMHI
MJL2KPO2
KPO1BRGA
CPRY
BM9L
BM13L
BM18L
BM19L BM30LBM30X
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
BNJR
CMHI
MJL2KPO2
KPO1BRGA
CPRY
BM9L
BM13L
BM18L
BM19L BM30LBM30X
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
BNJR
CMHI
MJL2KPO2
KPO1BRGA
CPRY
BM9L
BM13L
BM18L
BM19L BM30LBM30X
-6.9
-3.4-2.5 -14.0
Fixed
-0.7
-5.0
-2.8
-13.0
-2.9-5.0
-5.8
-15.9
-4.8-13.2
-4.7 -8.5
BANDUNG BASIN
SagulingDam
NORTH NORTH
10 km
July 2002 – June 2003
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
BNJR
CMHI
MJL2KPO2
KPO1BRGA
CPRY
BM9L
BM13L
BM18L
BM19L BM30LBM30X
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
BNJR
CMHI
MJL2KPO2
KPO1BRGA
CPRY
BM9L
BM13L
BM18L
BM19L BM30LBM30X
MJL1
DHYK
BJNS GDBG
PSCA
RCK2
UJBR
BNJR
CMHI
MJL2KPO2
KPO1BRGA
CPRY
BM9L
BM13L
BM18L
BM19L BM30LBM30X
-6.9
-3.4-2.5 -14.0
Fixed
-0.7
-5.0
-2.8
-13.0
-2.9-5.0
-5.8
-15.9
-4.8-13.2
-4.7 -8.5
BANDUNG BASIN
SagulingDam
NORTH NORTH
10 km
NORTH NORTH
10 km
July 2002 – June 2003
DHYK
GDBG
PSCA
RCK2RCK1
BNJR
CMHI
MJL2KPO2
KPO1BRGA
BM9L
BM13L
BM18L
DHYK
GDBG
PSCA
RCK2RCK1
BNJR
CMHI
MJL2KPO2
KPO1BRGA
BM9L
BM13L
BM18L
DHYK
GDBG
PSCA
RCK2RCK1
BNJR
CMHI
MJL2KPO2
KPO1BRGA
BM9L
BM13L
BM18L
-6.7 -3.3
Fixed
-5.7-2.6
-5.7
-3.6
-3.0-4.2
-1.1
-8.5
-8.3
BANDUNG BASIN
SagulingDam
NORTH NORTH
10 km
June 2003 – June 2005
DHYK
GDBG
PSCA
RCK2RCK1
BNJR
CMHI
MJL2KPO2
KPO1BRGA
BM9L
BM13L
BM18L
DHYK
GDBG
PSCA
RCK2RCK1
BNJR
CMHI
MJL2KPO2
KPO1BRGA
BM9L
BM13L
BM18L
DHYK
GDBG
PSCA
RCK2RCK1
BNJR
CMHI
MJL2KPO2
KPO1BRGA
BM9L
BM13L
BM18L
-6.7 -3.3
Fixed
-5.7-2.6
-5.7
-3.6
-3.0-4.2
-1.1
-8.5
-8.3
BANDUNG BASIN
SagulingDam
NORTH NORTH
10 km
NORTH NORTH
10 km
June 2003 – June 2005
GPS Derived Subsidence Rates (mm/month)
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia
0
5
10
15
20
25
30
35
40
45
BNJR CMHI DYHK MJL1 RCK1 RCK20
100
200
300
400
500
600Penurunan tanahVolume airtanahyang diambil
0
5
10
15
20
25
30
35
40
45
0
100
200
300
400
500
600SubsidenceExtracted groundwater
Subsi
den
ce (
cm)
Average volum
e of groundwater
extraction per month (in 1000 cubic-m
eter)0
5
10
15
20
25
30
35
40
45
BNJR CMHI DYHK MJL1 RCK1 RCK20
100
200
300
400
500
600Penurunan tanahVolume airtanahyang diambil
0
5
10
15
20
25
30
35
40
45
0
100
200
300
400
500
600SubsidenceExtracted groundwater
Subsi
den
ce (
cm)
Average volum
e of groundwater
extraction per month (in 1000 cubic-m
eter)
0
2
4
6
8
10
12
14
BNJR CMHI DYHK MJL1 RCK1 RCK2 CPRY KPO20
100
200
300
400
500
600Penurunan tanah
Volume airtanah yang diambil
0
2
4
6
8
10
12
14
BNJR CMHI DYHK MJL1 RCK1 RCK2 CPRY KPO20
100
200
300
400
500
600Penurunan tanah
Volume airtanah yang
Subsidence
Extracted groundwater
Average volum
e of groundwater
extraction per month (in 1000 cubic-m
eter)
Subsi
den
ce (
cm)
0
2
4
6
8
10
12
14
BNJR CMHI DYHK MJL1 RCK1 RCK2 CPRY KPO20
100
200
300
400
500
600Penurunan tanah
Volume airtanah yang diambil
Penurunan tanah
Volume airtanah yang diambil
0
2
4
6
8
10
12
14
BNJR CMHI DYHK MJL1 RCK1 RCK2 CPRY KPO20
100
200
300
400
500
600Penurunan tanah
Volume airtanah yang
Subsidence
Extracted groundwater
Average volum
e of groundwater
extraction per month (in 1000 cubic-m
eter)
Subsi
den
ce (
cm) WHY ?
• the registered groundwater abstraction volume does not reflect the real groundwater abstraction, and/or
• the land subsidence is also governed by other factors.
GPS survey results show that this hypothesis is not always true for all observed stations.
Land Subsidence and Groundwater AbstractionINITIAL HYPOTHESIS :
Land subsidence observed in several locations in Bandung
basin is caused by an excessive groundwater abstraction.
R = 0.643
R = 0.827
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia
-19.10
-24.55
-33.00
-69.38
-33.34
-41.60
-80
-75
-70
-65
-60
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
Dep
t (m
bel
ow g
roun
d)
Kahatex PT IKahatex PT IIKahatex PT III
Groundwater level variationsin Rancaekek area (3 wells)
-19.10
-24.55
-33.00
-69.38
-33.34
-41.60
-80
-75
-70
-65
-60
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
Dep
t (m
bel
ow g
roun
d)
Kahatex PT IKahatex PT IIKahatex PT III
Groundwater level variationsin Rancaekek area (3 wells)
697.8
697.9
698.0
698.1
698.2
698.3
698.4
698.5
698.6
Feb. 2000 Nov.2001 July 2002 June 2003 June 2005
Ellipsoidal height variationof GPS station : RCK2
= 56.9 cm
about 5 years
697.8
697.9
698.0
698.1
698.2
698.3
698.4
698.5
698.6
Feb. 2000 Nov.2001 July 2002 June 2003 June 2005
Ellipsoidal height variationof GPS station : RCK2
= 56.9 cm
about 5 years
SUBSIDENCE ANDGROUNDWATER
ABSTRACTION
in Rancaekek area
There iscorrelation !!
1 km
700 m
Water inundation in the road
Cracking and tilting of road
Groundwaterwells
IMPACT OFSUBSIDENCE AND
in Rancaekek area
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia
-80-70-60-50-40-30-20-10
0
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
Dept
h be
low
grou
nd (m
) Groundwater level variationMonitoring well : PT. Kahatex no. II RCK2 GPS point
Water Inundation
IMPACT OF SUBSIDENCE AROUND CMHI GPS STATIONHanging wall
Tilting of Infrastructures
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia
GPS survey method is a reliable method for studying and monitoring land subsidence should also be integrated with results obtained by Leveling, INSAR and Automatic Water Level Recorder.
Land subisdence in Bandung = f { excessive groundwater abstraction,
building load (?), tectonics (?), natural compaction (?), x1(?), … , xn (?) }
Further research is needed to clarify the real mechanism and pattern of land subsidence phenomena in Bandung.
CLOSING REMARKS
Hasanuddin Z. Abidin et al., 2006Bandung Institute of Technology, Indonesia