Focal validation mechanism for Lombok earthquake with image analysis of satellite radar and crust movement GPS observation

Lombok Earthquake on August 5 and August 19, 2018, traces of deformation were analyzed with satellite image data to determine vertical deformation in the form of uplift on the ground surface. Earthquake wave analysis provides data on the mechanism at the epicenter in the form of a fault, the major forces axis in the form of the P axis, as well as the T axis, in addition to location and strength. The results of the focal analysis showed that the Lombok earthquake was an earthquake on the rising fault, the results of satellite radar image analysis showed the corresponding results, where the maximum increase occurred on the lip of the fault block in the form of a hanging wall. The direction of the acting force is indicated by the Axis P, in accordance with the research results of the Lombok earth crust movement, namely the N-NE Direction

Subsidence analysis in DKI Jakarta using Differential Interferometry Synthetic Aperture Radar (DInSAR) Method

Land subsidence in DKI Jakarta influenced by several key factors, including the number of buildings that increase the load above the surface. There are still many people who explore groundwater sources as the principal source of clean water. Also,  the soil type is dominated by alluvial. This alluvial deposit can be one of the parameters for soil deformation in the form of land subsidence and uplift in land surface because basically, alluvial soil types have a susceptibility to the load support power above. So that the land subsidence in DKI Jakarta is relatively continuous. To find out the land subsidence is used a high-tech method,  Differential Interferometry Synthetic Aperture Radar (DInSAR) satellite image of radar data (SAR Sentinel-1A) in 2017. The result shows the land subsidence in the average value of DKI Jakarta which is about -3.685 cm/year and the highest subsidence happened in the West Jakarta district about -5.850 cm/year in average

PENENTUAN HARI LIBUR NASIONAL UMAT KRISTEN DI INDONESIA MENGGUNAKAN ALGORITMA ASTRONOMI MEEUS

Astronomically, Easter falls on the first Sunday following the first full moon after the vernal equinox. In Indonesia, Christian holidays including Easter are regulated by the Ministry of Religious Affairs based on the recommendation of Indonesian Church Union (PGI) and Bishops Conference of Indonesia (KWI). This study objective is to formulate a simple time marker by using Meeus Astronomical Algorithm to determine Christian holidays in Indonesian Gregorian calendar. Another objective is to evaluate the Christian holidays on Indonesian calendar between 1960 and 2015. Finally, this study would also provide prediction for future Christian holidays. This study finds out that the Christian holidays on Indonesian calendar are proven as methodologically accurate. It indicates that Meeus Astronomical Algorithm can produce accurate calculation for determining Christian holidays in Indonesia in the future. KEY WORDS:Meeus astronomical algorithm, christian holidays, Indonesian calendarSecara astronomis, perayaan Paskah jatuh pada hari Minggu pertama setelah bulan purnama pertama, setelah Matahari melalui Vernal Equinox. Di Indonesia tanggal libur keagamaan umat Kristen ditentukan oleh Kementerian Agama atas rekomendasi Persekutuan Gereja di Indonesia (PGI) dan Konferensi Wali Gereja Indonesia (KWI). Kajian ini bertujuan membuat program tanda waktu sederhana berdasarkan Algoritma Meeus untuk menentukan hari libur nasional umat Kristen di Indonesia pada kalender masehi, juga untuk evaluasi data hari libur umat Kristen dalam sejarah kalender Indonesia yang tercatat pada tahun 1960 hingga 2015 serta prakiraan hari libur umat Kristen di masa depan. Hasil menunjukkan bahwa tidak ditemui perbedaan pada Kalender Indonesia. Ini membuktikan bahwa hari libur umat Kristen di Indonesia tidak pernah menyimpang dari ketentuan. Dengan ini maka program Algoritma Meeus dapat direkomendasikan sebagai program tanda waktu hari libur nasional umat Kristen di Indonesia. KATA KUNCI: Algoritma astronomi meeus, hari libur Kristen, kalender nasiona

ANALISA PERBANDINGAN ANOMALI GRAVITASI DENGAN PERSEBARAN INTRUSI AIR ASIN (STUDI KASUS JAKARTA 2006-2007)

Aplikasi pada bidang geofisika, berupa pengukuran gravitasi dilakukan di lapangan dalam jangka waktu tertentu, dengan tujuan untuk mendeteksi perubahan kondisi bawah permukaan bumi. Dalam hal ini dilakukan pengukuran gravitasi di wilayah Jakarta untuk mendeteksi perubahan kondisi hidrologi Jakarta dalam kaitannya dengan fenomena intrusi air asin. Secara geografis daerah penelitian berada pada -6.35158 s.d -6.08655 LS dan 106.689 s.d. 106.955 BT. Pengolahan data gravitasi wilayah Jakarta dilakukan dalam 2 periode, yaitu periode I (September 2006) dan periode II (November–Desember 2007). Anomali gravitasi  tertinggi terdapat pada bagian pusat dan barat Jakarta ini mengindikasikan terjadinya fenomena subsidensi dan kekosongan massa akibat eksploitasi air tanah serta tekanan dari sejumlah gedung tinggi yang berpusat pada daerah tersebut. Anomali gravitasi terendah terdapat di bagian barat laut Jakarta yang bersesuaian konsentrasi nilai kepayauan tertinggi, mengindikasikan adanya intrusi air asin yang diakibatkan oleh adanya fenomena Conate Water yang menyusup  pada aquifer air tanah akibat eksplotasi air tanah berlebih. Hubungan pola aliran sungai dengan nilai kepayauan air, membuktikan adanya pengaruh sungai aquifer air tanah, namun dampaknya tidak terlalu berpengaruh terlebih pada aquifer dalam.   Gravity measurements are conducted in the field within a certain period in order to detect changes in the earth's surface conditions. We conducted gravity measurements in Jakarta to detect changes in hydrologic conditions in connection to salt water intrusion phenomena. The data processing performed in the two periods, the first period is September 2006 and the second one is November-December 2007. The highest gravity anomalies are in central and western parts of Jakarta. This implies the occurrence of mass subsidence and void due to the exploitation of ground water and the pressure from a number of high buildings based on the area. The lowest gravity anomaly takes place in the northwest of Jakarta. This condition is corresponding to the highest concentrations and show that there is salt water intrusion. The intrusion caused by Connate water that infiltrated the groundwater aquifer due to ground water overexploitation. The relationship between river flow patterns and salt concentration show that there is influence of groundwater aquifer of the river, but the influence is insignificant to deep aquifer

STUDI AWAL HUBUNGAN GEMPA LAUT DAN GEMPA DARAT SUMATERA DAN SEKITARNYA

Secara umum, wilayah Sumatera di bagi menjadi dua sumber gempa tektonik, yaitu pada zona subduksi di sepanjang laut dan pada zona-zona sepanjang patahan sistem sesar Sumatera di daratan. Sebagai studi awal untuk melihat interaksi antara kejadian gempa pada kedua daerah tersebut, maka dilakukan pendekatan dengan menganalisa gempa berdasarkan P-axis fokal mekanisme, rentang waktu kejadian, dan jarak dengan mengambil sampel dari data sejumlah gempabumi dirasakan yang pernah terjadi di laut dan di daratan pulau Sumatera selama tahun 2007 sampai 2009. Setelah dilakukan analisa P-axis dari hasil plot fokal mekanisme, jarak, dan selang waktu kejadian, diindikasikan bahwa kejadian gempa di laut mentrigger terjadinya gempa di darat. Didapatkan bahwa sebelum gempa darat 19 Juni 2008 dan 01 Oktober 2009, sejumlah gempa-gempa di lautnya memiliki kelurusan arah P-axis cenderung terhadap gempa di daratan.   Generally, Sumatera devided by 2 resources of tectonic earthquake, consist of subduction zone along the sea and subduction along fracture at Sumatera fault system in the land. As the begining study for observe interaction of earthquake from both of earthquake zone, do approximate to analyse the earthquake according P-axis of focal mechanism, stretches of time, and distance with take sample from a number of felt earthquake data that occur in the sea and the land of Sumatera at 2007 - 2009. After analyse P-axis from result of focal mechanism plot, distance, and time range, indicated that earthquake occur in the sea trigger earthquake occur in the land. We found that before earthquake 19 Juny 2008 and 1 October 2009, a number of earthquake in the sea have P-axis direction inclined turned to earthquake in the land

ANALISA VERTICAL TOTAL ELECTRON CONTENT DI IONOSFER DAERAH JAWA DAN SEKITARNYA YANG BERASOSIASI DENGAN GEMPABUMI YOGYAKARTA 26 MEI 2006 UTC

Kenyataan bahwa dampak gempabumi Yogyakarta 27 Mei 2006 (local time) memberikan dampak negatif bagi kehidupan menjadikannya salah satu bencana yang tidak memberikan waktu yang cukup lama untuk sebuah peringatan.  Sebelumnya, telah banyak dilakukan penelitian untuk membangun sebuah system yang diharapkan memberikan petunjuk untuk mem-pre-deteksi gempabumi. Salah satunya adalah pendekatan dengan Seismo-Ionospheric Coupling. Dalam pemikiran ini dijelaskan tahapan-tahapan yang terjadi di Ionosfer ketika gempabumi akan terjadi dan saat terjadi.Dalam tulisan ini dipilih Densitas Elektron dalam arah Vertical (Vertical Total Electron Content) di Ionosfer sebagai parameternya. Total Electron Content (TEC) adalah jumlah elektron dalam kolom vertikal (silinder) berpenampang seluas 1 m2 sepanjang lintasan sinyal perangkat GPS yang dilalui di lapisan ionosfer pada ketinggian sekitar 350 km.Dari analisa didapatkan, terjadi tiga kali penurunan nilai VTEC yang signifikan di daerah Jawa dan sekitarnya. Yaitu pada 18, 20 dan 22 Mei 2006. Namun setelah dikoreksi Dst Index, penurunan nilai VTEC pada tanggal 18 Mei 2008 berkaitan dengan gangguan magnetic. Selanjutnya pada tanggal 20 Mei 2006 dan 22 Mei 2006, penurunan nilai VTEC  diindikasikan sebagai akibat dari proses fisis Seismo-Ionospheric Coupling sebelum terjadinya gempabumi. Hal ini diperkuat dari koreksi Dst. Index yang tidak menunjukan adanya gangguan magnetik yang berarti.   Earthquake that struck Jogjakarta on May 27 2006 (local time) gives negative impact to life and it became of no awareness disaster. Previously, there are many researches that developed a system which can give signal to earthquake pre-detection. One of them is Seismo-Ionosperic Coupling. This research, explain phases in Ionospere before and after shock.Electron densities in vertical direction in Ionospere (Vertical Total Electron Content) is selected as parameter. Total  Electron Content  (TEC) is defined as the amount of electron in vertical column (cylinder) with cross-section of 1 m2 along GPS signal trajectory in Ionospere at arround 350 km of height.There are three times of significant decrease of VTEC value in Java and its surrounding, i.e. at 18, 20, 22 of May 2006. However, after corrected by Dst Index, the decrease VTEC value on May 18 2008 has relationship with magnetic disturbance. The decrease of VTEC value on May 20 and May 22 2006 is indicated as effect of Seismo-Ionosperic Coupling physical process before shock. This is supported by correction of Dst. index that shows there is no significant magnetic disturbance

KURSUS SINGKAT DAN PELATIHAN PENGOLAHAN BUAH PISANG MENJADI PISANG SALE DAN TEPUNG PISANG DI DESA GUMRIH, KECAMATAN PEKUTATAN, KABUPATEN JEMBRANA

ABSTRACT Banana is the main product of a dry land farming at Gumbrih. The shelf life of fresh banana is very short and hence it is a great effort to find out how to preserve the banana for longer period. A method that can be applied is that by processing the fresh banana into processed foods, which has longer shelf life and easily to be modified into several products, which still retains the flavour of fresh banana. It was found that the knowledge of the local people (Gumrih villagers) on technology and banana processing was quite low and hence the recent program on course and practices of banana processing into dried banana (pisang sale) and banana powder (tepung pisang) is absolutely important. The activities were held at Desa Gumbrih, Kecamatan Pekutanan, Kabuapten Negara, on Friday, 16 September 2005, attended by 26 participants. Instead of course and practical works, the activities also have been conducted by active two-direction discussion between participants and tutor members. Since participants were curious to follow all the activities and we suggest that similar program is significant to be held on those banana producers around Bali and the short practical course would be more beneficial if it can be associated with marketing of the products. </em