Kondisi tektonik dan tatanan geologi yang kompleks di Indonesia menghasilkan pembentukan bermacam-macam mineral. Salah satu mineral adalah timah pada wilayah Paparan Sunda, membentang dari Semenanjung Malaya, Kepulauan Riau, Kepulauan Singkep, Pulau Bangka, Kepulauan Tujuh, dan Pulau Belitung. Jalur timah ini umumnya telah mengalami erosi kuat pada waktu yang lama. Timah letakan adalah salah satu sumber daya mineral lepas pantai yang dapat ditambang. Umumnya mineral-mineral tersebut terperangkap di dalam lapisan sedimen permukaan berumur Kuarter. Pulau Bangka merupakan salah satu daerah yang dikenal sebagai kepulauan timah. Pusat Penelitian Pengembangan Geologi Kelautan (PPPGL) pada tahun 1994 telah melakukan penyelidikan geologi dan geofisika kelautan di daerah perairan Bangka Utara (Lembar Peta 1114), dengan sekala peta 1 : 250.000. Dengan teknologi khususnya seismik refleksi dan penafsirannya, diharapkan akan ada temuan-temuan cadangan timah baru. Morfologi dasar laut daerah penyelidikan digambarkan oleh pola kontur batimetri relatif rapat di bagian barat pantai. Pola ini mencerminkan suatu sisi punggungan (homoklin) dan berarah timur laut – barat daya. Diantara PulauTujuh dan Pulau Bangka pola kontur membentuk tutupan-tutupan (closure) dan membentuk suatu kelurusan berarah timur laut – barat daya berupa cekungan-cekungan kecil merupakan alur selat P. Tujuh dan P. Bangka. Hasil penafsiran rekaman seismik refleksi kondisi geologi bawah permukaan dasar laut dapat dipisahkan menjadi dua sekuen yaitu sekuen A dan sekuen B. Sekuen B adalah sekuen paling bawah (acoustic basement) yang terdiri dari subsekuen B1, B2 dan B3, tidak semua subsekuen ini terekam karena umumnya horizon reflektornya sulit diidentifikasi dan umumnya tertutup oleh pantulan ganda (multiple). Sekuen A adalah sekuen yang diendapkan diatas sekuen B, dibedakan dengan sekuen B yang berada dibawahnya oleh bidang erosi, sekuen A ini terdiri dari subsekuen A1 dan A2. Kedua subsekuen ini jika disebandingkan secara stratigrafi berdasarkan Mangga dan Jamal serta Aleva, merupakan “Young Sedimentary Complex” terbentuk pada Kala Holosen. Kata Kunci : Identifikasi Alur Purba, Seismik Pantul Dangkal, Perairan Bangka Utara, Lembar Peta 1114. In Indonesia minerals occurrence were controlled by tectonic process and regional geological setting. One mineral is tin in the Sunda shelf, area which stretch from Malaya Peninsula, Riau Islands, Singkep Islands, Bangka Island, Tujuh Islands and Belitung Island. This tin belt was strongly eroded in the long period of time. Tin placer is an offshore mineral resource which was already exploited. Generally the mineral is trapped in the surface sediment layers, of Quartenary age. Bangka Island is well known one of many tin archipelago. Marine Geological Institute (MGI) in 1994 has done geological and geophysical mapping in North Bangka waters (Map Sheet, 1114), with map scale 1 : 250.000. The technology used especially seismic reflection and its interpretation was expected discovery of new tin reserves. Sea bottom morphology of area investigation is depicted by bathymetric contour pattern relatively closed to the western coast. This pattern is a ridge (homoklin) of northeast - southwest direction. Between Pulautujuh and Bangka Islands contour pattern is closure and elongated northeast-southwest as small basins which formed a channel between P. Tujuh and P. Bangka. The interpretation of seismic reflection record showed subsurface geology condition divided in to two sequences A and B. Sequence B is a basement acoustic consisted of subsequence B1, B2 and B3, these subsequence were not all recognised due to generally its horizon reflector is difficult to be identified and is generally covered up multiple. Sequence A was deposited above sequence B and was differentiated by erosional truncation. Sequence A is consisted of subsequence A1 and subsequence A2. Both subsequences correlated to Mangga and Jamal, and also Aleva, stratigraphically representing " Young Sedimentary Complex" formed in Holocene. Keyword : Paleochannel Identification, Shallow Reflection Seismic, North Bangka Waters, Map Sheet 1114.

Daerah penelitian dicirikan oleh morfologi dasar laut yang terjal dan bergelombang dengan kedalaman bervariasi dari 40 meter di bagian timur hingga 2150 meter di bagian utara. Berdasarkan data rekaman seismik pantul dapat diidentifikasi adanya struktur geologi berupa sesar, lipatan, dan diapir. Kenampakan struktur-struktur tersebut ditandai dengan adanya lapisan yang patah, bergelombang, dan bentuk kubah. Sesar umumnya berarah timurlaut-baratdaya, dimana perkembangannya diduga sangat dipengaruhi tektonik regional terutama sesar utama Palu-Koro yang ada di daratan Pulau Sulawesi dan menerus ke laut sekitar lokasi penelitian. Kata kunci: morfologi, struktur geologi, sesar Palu-Koro, Pasangkayu The study area is characterized by the steep sea floor morphology with the depth from 40 metres in the east to 2150 metres in the north. On the basis of reflection seismic records, the geological structures such as faults, folds, and diapirs can be recognized. The appearance of such structures is signed by the faulted, wavy and domed layers. The faults in general have NE –SW direction, where it development possibly influenced by the regional Palu-Koro Fault present in Sulawesi island that continue to the study area. Keywords: morphology, geological structures, Palu –Koro Fault, Pasangkayu

Peta anomali magnetik menunjukkan bahwa perairan Bangka Belitung dicirikan oleh pasangan tinggian dan rendahan panjang gelombang anomali dengan amplitudo -200 nT—500nT. Sedangkan dari peta distribusi kerentanan magnetik, tinggian magnetik Belitung dibatasi oleh nilai kerentanan magnetik antara 0,001 cgs unit dan 0,003 cgs unit. Anomali positip rendah dicirikan oleh nilai kerentanan magnetik batuan antara 0,001-0,003 cgs unit merupakan benda intrusif bawah laut yang diduga berupa pluton granitik jenis granit-biotit yang berasosiasi dengan mineral kasiterit. Pluton granitik tersebut sama seperti granit yang berafiliasi dengan endapan timah di daratan Pulau Belitung. Misalnya singkapan granit yang terdapat di sekitar pantai Gembira yang menunjukkan tipe granit biotit porfiritik dengan fenokris ortoklas. Kata Kunci: anomali magnetik, kerentanan magnetik, granit, Bangka Belitung Magnetic anomaly map shows that the Bangka Belitung waters are characterized by a pair of hight and low long-wave amplitude anomalies values of -200 nT—500 nT. While the distribution map of magnetic susceptibility magnetic high of Belitung is limited magnetic susceptibility values of 0.001 cgs units and 0.003 cgs units. Positive anomaly of low magnetic is characterized susceptibility values between 0.001 to 0.003 cgs units suggested as a body of submerged intrusive rock body granitic plutons of granite biotite type associated with casiterite mineral. Granitic plutons are the same as granite affiliated with tin deposits in the mainland island of Belitung. For example there are granite outcrops around the Gembira coast that shows the type of porphyritic biotite granite with phenocrysts ortoclas. Keywords: Magnetic anomaly, magnetic susceptibility, granite, Bangka Belitung

Data yang digunakan untuk kajian ini adalah : kecepatan sedimentasi, daya dukung tanah, dan analisis besar butir. Kecepatan sedimentasi secara vertikal berkisar antara 1.023 sampai 3.835 cm/tahun dan pertumbuhan pantai dari tahun 1999 hingga tahun 2000 adalah 7,287 cm. Volume sedimen yang terendapkan selama tiga tahun adalah 266.621.000 m2 x 0,07287 meter = 19.428.672,27 m3. Daya dukung tanah diketahui dari hasil uji Standart Penetration Test (SPT) dari 0 m hingga kedalaman 24,45 m memiliki kepadatannya relatif agak kaku (stiff) yang merupakan endapan pantai. Kedalaman 24,00 sampai 41,00 meter memiliki kepadatannya relatif sangat kaku (very stiff) hingga keras (hard). Dari nilai indeks plastisitasnya dapat dikatakan bahwa semua jenis tanah lempung (CH) di daerah penelitian memiliki sifat plastisitas tinggi dan kohesif. Hasil analisis besar butir menunjukkan bahwa secara umum jenis tanah/sedimen di daerah penelitian terdiri dari sedimen yang memiliki fraksi halus berupa persentasi pasir sangat halus terbesar kemudian fraksi lanau. Berdasarkan uji konsolidasi dari contoh pemboran memperlihatkan pada tanah/sedimen di daerah penelitian yang berfraksi halus memiliki tingkat kompresibilitas tanah sedang hingga tinggi. Kata kunci : kecepatan sedimentasi, standard penetration test, besar butir, Cirebon Data used for this study are sedimentation rate, soil bearing capacity, and grain size analysis. Rate of sedimentation in vertical is among 1.023 to 3.835 cm/year and beach growth from years 1999 until year 2000 about 7,287 cm. Sediment are deposited to reach volume up to three year about 266.621.000 m 2 x 0,07287 m = 19.428.672,27 m 3 . Bearing capacity of soil from Standard Penetration Test (SPT) to the depth of 24,45 meters shows a stiff densities and constitute of beach sediment. From the depth of 24,00 to 41,00 meters shows densities a very stiff until hard densities. Their plasticity index of all clay in the study area are hingh plasticity (CH) and cohesive. From the grainsize analysis shows that all the soil/sediments in the study area are fine sediment which are very fine sand and silt. The fine sand are more dominant than the silt. Based on consolidation test from drilling samples those are also soil/sediments of fine fraction show a compressibility value from medium to high. Keywords: sedimentation rate, standard penetration test, grain size, Cirebon

Tax is one of the main sources of revenue for a country that is paid by the public. Taxes are also collection fees that can be imposed by the government based on the provisions of tax laws and regulations. The research method is qualitative deductive. Data collection techniques are observation, interviews, and documentation. The analysis technique used is data collection, data reduction, data presentation, and concluding. The results of the study explain that several factors that cause the first less than optimal motor vehicle tax receipts are community compliance whereas in Maros district the level of community compliance with motor vehicle tax payments is still low, as evidenced by the number of vehicles that do not re-register. Furthermore, the performance of the officers who were assessed was still lacking in discipline and the last one was the target that was too high so that it was very difficult for the Maros Revenue Unit to realize it by the end of the year. The research can be used as a reference in analyzing the challenges of motor vehicle tax receipts because previous research focused on the motor vehicle tax revenue services system at the Technical Services Unit Office Revenue.