%A 1515051034 Dian Sanjaya
%T ?ANALISIS HORIZONTAL GRADIENT, TILT ANGLE, MODEL 2D, DAN
MODEL 3D GAYABERAT DALAM IDENTIFIKASI ZONA SESAR
DAERAH PANAS BUMI GUNUNG UNGARAN, JAWA TENGAH?
%X Mount Ungaran is a geothermal area where there is a geothermal system in the
area that is characterized by certain characteristics such as the presence of hot
springs, fumaroles, hot soils, deposits of travertine and altered rocks. The location
of geothermal manifestations is mainly located on the northwest, southwest and
southeast slopes of Mount Ungaran. This research was conducted using gravity
method to identify fault zones which is controller of geothermal system, in this
case in Mount Ungaran area, using Horizontal Gradient and Tilt Angle. The
regional zone at study area is at a depth of 3.5 km and the residual zone at a depth
of 0.6 km. The manifestations of Nglimut, Diwak, Banaran, Gedongsongo, and
Kendalisodo are associated with the existence of faults. Fault structures are
scattered in the study area at North West-South East and North-South direction.
There are 5 types of rock lithology, namely Gajahmungkur Formation (2.39 gr /
cc), Kaligesik Formation (2.64 gr / cc), Jongkong Formation (2.51 gr / cc),
Penyatan Formation (2.4 gr / cc), and Basement (3.1 gr / cc). The existence of
Basement layer based on the research final result model is estimated placed in
Kaligetas Formation. High bouguer anomaly value is influenced by Kaligesik
Formation which exposed to the surface and low bouguer anomaly is caused by
the presence of magma chamber that has high porosity. Ungaran Mountain
geothermal reservoir is in Gedongsongo, exactly, at a depth until 2700 m below
sea level.
Keywords: gravity, faults, Mount Ungaran

Gunung Ungaran merupakan salah satu area sistem panas bumi yang ditandai
dengan mata air panas, fumarol, tanah panas, endapan travertin dan batuan
teralterasi. Lokasi manifestasi panas bumi terutama terletak di lereng Barat Laut, Barat Daya dan Tenggara Gunung Ungaran. Penelitian ini dilakukan
menggunakan metode gayaberat untuk mengidentifikasi zona sesar sebagai
pengontrol sistem panas bumi daerah Gunung Ungaran menggunakan Horizontal
Gradient dan Tilt Angle. Zona regional pada daerah penelitian memiliki kedalaman 3.5
km dan zona residual memiliki kedalaman 0.6 km. Manifestasi Nglimut, Diwak,
Banaran, Gedongsongo, dan Kendalisodo berasosiasi dengan keberadaan sesar.
Struktur sesar tersebar di daerah penelitian dengan arah Barat Laut-Tenggara dan
Utara-Selatan. Terdapat 5 jenis litologi batuan yaitu Formasi Gajahmungkur (2.39
gr/cc), Formasi Kaligesik (2.64 gr/cc), Formasi Jongkong (2.51 gr/cc), Formasi
Penyatan (2.4 gr/cc), dan Basement (3.1 gr/cc), Basement pada model hasil
penelitian diperkirakan berada pada Formasi Kaligetas. Nilai anomali bouguer
tinggi dipengaruhi oleh Formasi Kaligesik yang tersingkap ke permukaan,
kemudian anomali bouguer rendah disebabkan karena adanya kantong magma
yang memiliki porositas tinggi. Reservoar panas bumi Gunung Ungaran berada di
Gedongsongo dengan kedalaman mencapai 2700 m di bawah permukaan laut.
Kata kunci: gayaberat, sesar, Gunung Ungaran
%C Universitas Lampung
%D 2019
%I Fakultas Teknik
%L eprints56554