| Summary: | Gunungsewu located at Gunungkidul reg ency is known as dry and plain
area which is relative difficult to get fresh water ecspecially at drought season.
The geological condition which is composed from limestone (karst) potentially
creates karstic aquifer system. To estimate it based on physical parameters
contrast of conductivity caused by water existance in limestone cavity, it requires
appropriate geophysics method. It is VLF-EM method.
The aims of this research are to know the direction, the depth of Seropan
karstic aquifer pathways and to make its 2D modeling. The location is at
Gombong village, Semanu district, Gunungkidul regency with latitude and
longitude of 8,014
0
S and 110,67
0
E respectively. It had been done for 12 days
from 15th until 26th September 2013. Qualitative interpretation used Fraser filter,
Karous Hjelt filter which generates equivalent current density. For quantitative
interpretation was based on inverse modeling which had generated resistivity
contour model.
The result of qualitative interpretation shows that the flowing direction of
karstic aquifer from the North of Seropan cave to the South through Gombong
village. It is estimated that there are three karstic aquifer pathways, those are first
with 30 of depth in the North and 35 m of depth in the South, second with 40 m of
depth in the North and 40 m of depth in the South, and third with 25 of depth in
the North and 40 m of depth in the South. Karstic aquifer pathways from 2D
modeling also flows from the North to the South in �!\" � �'�๳ of width and
6.44 % of error noted by low resistivity anomalies 500 ohm-m. The first pathway
flows from 182 m of elevation in the north to 144 m in the south, second flows
from 163 m of elevation in the north to127 m in the south, and third flows from
163 m of elevation in the north to 127 m in the south. The depth of river has
variation from 25 until 50 meter.
Gunungsewu located at Gunungkidul reg ency is known as dry and plain
area which is relative difficult to get fresh water ecspecially at drought season.
The geological condition which is composed from limestone (karst) potentially
creates karstic aquifer system. To estimate it based on physical parameters
contrast of conductivity caused by water existance in limestone cavity, it requires
appropriate geophysics method. It is VLF-EM method.
The aims of this research are to know the direction, the depth of Seropan
karstic aquifer pathways and to make its 2D modeling. The location is at
Gombong village, Semanu district, Gunungkidul regency with latitude and
longitude of 8,014
0
S and 110,67
0
E respectively. It had been done for 12 days
from 15th until 26th September 2013. Qualitative interpretation used Fraser filter,
Karous Hjelt filter which generates equivalent current density. For quantitative
interpretation was based on inverse modeling which had generated resistivity
contour model.
The result of qualitative interpretation shows that the flowing direction of
karstic aquifer from the North of Seropan cave to the South through Gombong
village. It is estimated that there are three karstic aquifer pathways, those are first
with 30 of depth in the North and 35 m of depth in the South, second with 40 m of
depth in the North and 40 m of depth in the South, and third with 25 of depth in
the North and 40 m of depth in the South. Karstic aquifer pathways from 2D
modeling also flows from the North to the South in �!\" � �'�๳ of width and
6.44 % of error noted by low resistivity anomalies 500 ohm-m. The first pathway
flows from 182 m of elevation in the north to 144 m in the south, second flows
from 163 m of elevation in the north to127 m in the south, and third flows from
163 m of elevation in the north to 127 m in the south. The depth of river has
variation from 25 until 50 meter.
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