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"The present thesis describes significant new insight into the seismotectonics of this Central India tectonic zone, based on thorough magnetotelluric studies. The main objectives of the present study are: (i) to delineate subtrappean sediments across the NSL region along four different traverses, (ii) to understand the characterization of geo-electrical structure of the crust and examine the nature of geo-electrical signatures of the known faults, (iii) to integrate the results with other geophysical data such as seismicity, gravity and heat flow, in order to understand the tectonic scenario of the region. "

"ABSTRAKJawa bagian tengah merupakan salah satu bagian dari Busur Sunda yang mempunyai zona subduksi yang sangat aktif. Aktivitas tumbukan lempeng telah membangkitkan beberapa bencana alam, seperti: gempabumi, tsunami dan gunung meletus yang banyak menelan korban jiwa. Penelitian ini bertujuan untuk: 1 mengetahui struktur kerak bumi Jawa bagian tengah, dilihat dari: ketebalan kerak, rasio Vp/Vs dan model kecepatan gelombang S, serta 2 mengidentifikasi keberadaan zona kecepatan rendah dan slab subduksi. Metode yang dilakukan adalah dengan melakukan analisis fungsi penerima dari data teleseismik yang terekam pada 10 sensor broadband 3 komponen dari jaringan seismograf BMKG Badan Meteorologi, Klimatologi, dan Geofisika dan 64 sensor short period 3 komponen dari jaringan MERAMEX MERapi AMphibious EXperiment terpilih di Jawa bagian tengah. Model kecepatan gelombang S dan rasio Vp/Vs di bawah stasiun didapatkan dengan melakukan inversi fungsi penerima menggunakan metode non-linear Algoritma Neighbourhood NA . Model kecepatan lokal hasil NA dari penelitian ini digunakan untuk memigrasikan amplitudo fungsi penerima ke kedalaman. Ketebalan kerak bumi di Jawa bagian tengah bervariasi dari 19 km hingga 60 km dan relatif lebih tebal di bawah busur pegunungan sebagai kompensasi massa dari isostasi. Zona kecepatan rendah dapat diidentifikasi pada kedalaman 10-25 km di bagian Selatan Jawa bagian Tengah berkaitan dengan aktivitas geotermal dari gunung api aktif Merapi-Lawu Merapi Lawu Anomaly . Zona kecepatan rendah juga terdapat pada kedalaman lebih dari 100 km dan berkaitan dengan lelehan parsial yang naik dari slab subduksi dan bermigrasi mengisi kantong magma gunung api di Jawa Tengah. Keberadaan Slab Subduksi Indo-Australia dengan cukup baik dapat digambarkan dari fase konversi Ps beberapa stasiun seismik. Kedalaman slab sekitar 100-120 km di Selatan Jawa Tengah dan menukik cukup tajam di bagian Tengah hingga ke agak Utara pada kedalaman 200-220 km. Terdapat ketidakmenerusan slab di Utara Jawa tengah kemungkinan berasosiasi dengan adanya lubang pada slab yang didukung beberapa penelitian sebelumnya. Keberadaan Fragmen Benua Gondwana yang memberikan fase konversi Ps kuat di bawah Moho berada pada kedalaman 40-50 km dan mengobduksi kerak yang berada di bawah batuan dasar Zona Pegunungan Selatan Jawa mengakibatkan kompresi dan lipatan pada zona ini.

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ABSTRACTCentral Java as a part of the Sunda Arc has a very active subduction zone. Plate collision activity has generated several natural disasters, such as earthquakes, tsunamis and volcano eruptions caused many casualties. This study aims to 1 to know the characteristic of crustal structure in Central Java crustal thickness, Vp Vs ratio and S wave velocity models, and 2 to identify the presence of low velocity zones and subduction slabs. The method was using receiver function analysis of teleseismic data recorded on 10 broadband three component seismometers from BMKG network Meteorology, Climatology and Geophysics Agency and 64 selected short period three component seismometers from MERAMEX MERapi AMphibious EXperiment network at Central Java. The inversion was performed using non linear Neighborhood Algorithm NA . The local velocity model of NA was used to migrate the amplitude of the receiver function to depth. The thickness of the earth rsquo s crust in Central Java is between 19 to 60 km and relatively thicker under the volcanic arc as the mass compensation of isostation. The low velocity zone can be identified at depth 10 to 25 km in the Southern part of Central Java that is related to the geothermal activity of Mt. Merapi Lawu Merapi Lawu Anomaly . The low velocity zone also exist at depth over 100 km and is associated with partial melting of subduction slab. The presence of Indo Australian subduction slab can be observed from the Ps conversion phase of several station. The depth of the top slab is at depth of about 100 to 120 km in the South of Central Java and steeper to the North at depth of about 200 to 220 km. There is a gap of slab in northern Central Java which associated with tearing of slab supported by previous studies. While the presence of Gondwana Continental Fragment is at depth of about 40 to 50 km in the Southern Mountain of Java resulted in compression and folding in this zone."

"Under normal conditions, a geomorphic system establishes a steady state with well-adjusted energy and material flow. Rainfall supplies the potential energy to channels and gradient converts it into kinetic energy. Thus, as a result of this process, erosion occurs. Hence, the moment adjustment between energy and material will be disturbed, the system will be distorted and the result will be slope instability. The present paper has been designed to evaluate the mechanism of slope instability with special reference to Central Himalayan district of India."

"Karwa A, Rai MK. 2010. Hitherto unreported Agaricus species of Central India. Nusantara Bioscience 2: 141-145. Melghat forest region from Central India was surveyed for occurrence of medicinal and culinary mushrooms during the years 2005-2008. Out oftotal 153 species, ten species of Agaricus were recorded from different localities. Of these, seven species namely Agaricus bitorquis, A.subrufescens, A. augustus, A. placomyces, A. essettei, A. basioanolosus and Agaricus sp. nov (a new species) are being reported for thefirst time from the region. The commercial button mushroom Agaricus bisporus lacks good breeding characters due to its bisporic nature. These wild cousins of the button mushroom can definitely prove to be a good source of genetic manipulations to the existing strains and also to develop new strains with improved characters"

"Wilayah Panas Bumi “X” merupakan bagian dari Busur Banda bagian Vulkanik Dalam. Busur Banda ini merupakan hasil dari subduksi antara Lempeng Indo-Australia dengan Lempeng Eurasia sehingga menghasilkan zona vulkanik yang menguntungkan terbentuknya sistem panas bumi. Identifikasi struktur geologi penting untuk memetakan zona permeabilitas tinggi di Wilayah Panas Bumi “X”, Nusa Tenggara Timur. Identifikasi struktur geologi pada penelitian ini menggunakan metode gravitasi dan pemetaan kelurusan berdasarkan Digital Elevation Model (DEM). Data anomali Bouguer lengkap dipisahkan menjadi anomali residual dan anomali regionalnya menggunakan filter Moving Average (MVA). Berdasarkan analisis spektrum, kedalaman rata-rata dari zona anomali gravitasi regional adalah 49,44 km, sedangkan kedalaman zona anomali gravitasi residual rata-rata adalah 3,612 km. Berdasarkan pemetaan kelurusan berdasarkan DEM, teridentifikasi kelurusan struktur geologi yang sebagian besar menunjukkan orientasi timur laut-barat daya. Hal ini cocok dengan sesar yang teridentifikasi dari data anomali residual berdasarkan analisis derivatif yang sebagian besar menunjukkan orientasi yang hampir sama. Orientasi ini juga cocok dengan sesar yang dilaporkan pada peta geologi yang menunjukkan orientasi yang mirip. Selain itu, pemetaan kelurusan berdasarkan DEM mampu menunjukkan keterkaitan antara keberadaan mata air panas dengan zona yang memiliki nilai Fault and Fracture Density (FFD) tinggi serta keterkaitan antara zona FFD sedang hingga tinggi dengan keberadaan sesar yang dilaporkan oleh peta geologi. Penelitian ini juga menghasilkan informasi mengenai zona permeabilitas tinggi yang berpotensi untuk diteliti lebih lanjut.

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The "X" Geothermal Area is part of the Inner Banda Volcanic Arc. This Banda Arc is the result of subduction between the Indo-Australian Plate and the Eurasian Plate, creating a favorable volcanic zone for the formation of geothermal systems. The identification of geological structures is crucial for mapping high-permeability zones in the "X" Geothermal Area, East Nusa Tenggara. In this study, the identification of geological structures was conducted using gravity methods and lineament mapping based on Digital Elevation Model (DEM). The complete Bouguer anomaly data was separated into residual and regional anomalies using a Moving Average (MVA) filter. Based on spectrum analysis, the average depth of the regional gravity anomaly zone was found to be 49.44 km, while the average depth of the residual gravity anomaly zone was 3.612 km. Based on lineament mapping from DEM, geological structures were identified predominantly showing a northeast-southwest orientation. This is consistent with the identified faults from the residual anomaly data through derivative analysis, which also exhibited a similar orientation. This orientation is also in agreement with reported faults on the geological map showing a similar orientation. Furthermore, lineament mapping from DEM was able to indicate the correlation between the presence of hot springs and zones characterized by high Fault and Fracture Density (FFD) values, as well as the correlation between moderate to high FFD zones and the reported faults on the geological map. This research also provides information regarding high-permeability zones that have the potential for further investigation."

"ABSTRAKPengamatan sinyal gempa bumi di seluruh dunia memungkinkan para ahli seismologi untuk mengetahui struktur internal dari bumi terutama kerak buminya. Dalam penelitian ini, dilakukan analisa terhadap receiver function dan dispersi gelombang permukaan di daerah Jawa bagian Barat, Indonesia. Penelitian ini bertujuan untuk : (1) Memodelkan struktur kecepatan kerak bumi di daerah Jawa bagian barat yang didapatkan dari join inversi receiver function dan dispersi gelombang permukaan, (2) Mengetahui ketebalan kerak bumi di daerah Jawa bagian barat dan (3) Mengetahui keberadaan Low Velocity Zone ( zona kecepatan rendah). Receiver function dihitung dari data gempa dengan magnitude lebih besar dari 5 dengan jarak episenter 30o - 90o dengan teknik iterasi dekonvolusi. Dispersi gelombang permukaan diperoleh dengan menggunakan analisis frekuensi waktu dari gempa dengan manitude lebih besar dari 5 dengan jarak 30o - 40o. Dari hasil join inversi yang dilakukan, didapatkan model kecepatan struktur kerak bumi di daerah Jawa Bagian Barat dengan ketebalan kerak bervariasi pada tiap stasiun yaitu antara 30-38 km. Ketebalan kerak paling tebal terdapat di Zona Pegunungan Bayah dan Zona Bandung. Struktur kecepatan kerak bumi pada stasiun yang berada pada zona fisiografi yang sama memiliki kesamaan pola kecepatan Vs.

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ABSTRACT

Earthquake signal observations around the world allow seismologists to obtain the information of internal structure of the Earth especially the Earth's crust. In this study, receiver functions and surface wave dispersion analized in Western Java, Indonesia. The objectives of this study (1). Modelling crustal structure velocity of western java obtained from joint inversion of teleseismic data receiver function and surface wave dispersion (2) To find out the earth's crust thickness in Western Java and (3). To find out the existence of low velocity zone. Receiver function were calculated from earthquakes with magnitude more than 5 and at distance 30o - 90o, with iterative deconvolution technique. Surface wave dispersions were calculated using frequency time analysis from earthquakes at distance 30o - 40o. Crustal velocity structure model in Western Java obtained from joint inversion receiver function and surface wave dispersion, and crustal thickness beneath each station is about 30-38 km. Pegunungan Bayah zone and Bandung zone has the most thick earth crust. Crustal structure velocity has identically pattern which are in the same physiography zone."