Edukasi Fenomena Amblesan-intrusi Air Laut dan Penanggulangannya di Semarang Utara

Telah dilaksanakan kegiatan kepada masyarakat berupa edukasi fenomena amblesan intrusi air laut dan penanggulangannya di Semarang utara. Latar belakang kegiatan ini adalah untuk memberikan pemahaman kepada masyarakat mengenai fenomena amblesan intrusi air laut dan upaya yang dilakukan untuk menanggulangi fenomena tersebut. Fenomena amblesan intrusi air laut ini diakibatkan pengambilan air tanah yang berlebihan sehingga lapisan tanah menjadi turun serta naiknya muka air laut yang dapat menyebaban air tanah terkontaminasi air laut sehingga menjadi air payau. Untuk mengatasi masalah tersebut dilakukan kegiatan sosialisasi kepada masyarakat melalui kegiatan memberikan pemahaman terhadap masyarakat dalam bentuk pengenalan materi, diskusi dan pelatihan tentang cara-cara mngetasi amblesan dan intrusi air laut. Hasil yang diperoleh menunjukkan bahwa pada umumnya masyarakat mengenal fenomena amblesan dan intrusi air laut hanya sebatas pengalaman sehari-hari dan terkesan sudah terbiasa dengan fenomena tersebut. Sosialisai dan pelatihan dengan menerapkan teknologi tepat guna yang berkesinambungan perlu dilakukan untuk mengatasi fenomena amblesan intrusi air laut

Geo-Electric Resistivity Method of Dipole-Dipole Configuration For Cavities Model 2D in Karst Area of Temurejo Village Gubug Sub-district Central Java District

The purpose of this research is to mapping cavities in karst area in Temurejo Village, Karangrayung, Grobogan using geoelectric resistivity method and dipole-dipole configuration. Measurement consist of six lines using Multichannel S-Fields geoelectric instrument. Apparent resistivity data processing use two software, Res2DInv ver. 3.56.22 and Voxler 4.0. The result is lithology of the research location can be interpret consist of sand-silt, carbonate-silt rock, carbonate-sand rock, and carbonate rock with resistivity range 15,3-4919 Ωm. There are resistivity value anomaly in line of 1,2,3,4,5, and 6 on the carbonate rocks layer, the value is more than 4949 Ωm which can interpret as a cavity. On the first line, cavities are at depths of 20 m and 12 m, on second line are at depths of 17 m and 12 m, on third line is at depth of 19 m. Cavity continuously at depth of 18 m on fourth, fifth and sixth lines. This cavities at the depth >23 m beneath eath surface

Pemisahan Anomali Regional dan Residual Data Gayaberat Studi Kasus di Kota Lama Semarang

Research has been carried out using gravity methods to identify subsurface structures in the region of Kota Lama Semarang as a preliminary survey for disaster mitigation purposes. In processing gravity data to identify subsurface structures, several processing stages are carried out. The initial step is to make the initial correction in the form of tide correction and float correction then a further correction is performed until a complete Bouguer anomaly contour is obtained. From the complete Bouguer anomaly, regional and residual gravity anomalies can be separated. The separation of regional anomalies from Bouguer anomalies in this study uses the moving average method while residual anomalies are obtained by subtracting Bouguer anomalies from regional anomalies. In the study of identification of subsurface structures it is important to conduct regional and residual anomaly separations to interpret geological structures and obtain the targets sought. Regional anomaly values in the region of Kota Lama Semarang are between 28.0 mGal - 28.4 mGal while for residual anomalies have between 31.6 mGal - 32.8 mGal

Pembuatan Buku Cerita IPA Yang Mengintegrasikan Materi Kebencanaan Alam Untuk Meningkatkan Literasi Membaca Dan Pembentukan Karakter

Tujuan penelitian untuk mengembangkan buku cerita IPA yang mengintegrasikan materi kebencanaan alam untuk siswa kelas IV SD. Penelitian ini dilaksanakan dengan menggunakan desain penelitian dan pengembangan. Hasil yang diperoleh dalam uji kevalidan yaitu kategori sangat tinggi untuk dimensi materi dan tampilan, kategori tinggi untuk dimensi bahasa. Keterbacaan sudah sesuai dengan tabel konversi SMOG dengan diperkuat metode pertanyaan. Keberterimaan buku cerita IPA memperoleh kategori sangat tinggi. Keefektifan buku cerita IPA dapat meningkatkan literasi membaca pada kategori sedang. The purpose of study to develop science books that integrate natural disaster materials for fourth grade students. This study is conducted by using a design research and development. The results obtained in the test validity of the other category of very high dimensional material and look, high category for the language dimension. Readability is in conformity with the SMOG conversion table with reinforced method of inquiry. Acceptance of science books category of very high gain. The effectiveness of science books can improve reading literacy in the medium category

Pemisahan Anomali Regional dan Residual Data Gayaberat Studi Kasus di Kota Lama Semarang

Research has been carried out using gravity methods to identify subsurface structures in the region of Kota Lama Semarang as a preliminary survey for disaster mitigation purposes. In processing gravity data to identify subsurface structures, several processing stages are carried out. The initial step is to make the initial correction in the form of tide correction and float correction then a further correction is performed until a complete Bouguer anomaly contour is obtained. From the complete Bouguer anomaly, regional and residual gravity anomalies can be separated. The separation of regional anomalies from Bouguer anomalies in this study uses the moving average method while residual anomalies are obtained by subtracting Bouguer anomalies from regional anomalies. In the study of identification of subsurface structures it is important to conduct regional and residual anomaly separations to interpret geological structures and obtain the targets sought. Regional anomaly values in the region of Kota Lama Semarang are between 28.0 mGal - 28.4 mGal while for residual anomalies have between 31.6 mGal - 32.8 mGal

Penelitian Intrusi Air Laut Di Kawasan Semarang Utara Dengan Metode Gaya Berat Mikro Antar Waktu

Telah dilakukan penelitian intrusi air laut dengan menggunakan metode Gaya berat mikro antar waktu di Semarang Utara. Penelitian ini dilatarbelakangi oleh beberapa fenomena yang selama beberapa tahun terakhir ini terajadi di lokasi penelitian, yaitu amblesan, rob, banjir dan air sumur gali penduduk berasa asin yang disebabkan oleh intrusi air laut. Pengukuran gaya berat menggunakan gravimeter tipe Scintrex Autograv CG-5. Periode pengukuran gaya berat adalah Oktober di 120 titik yang tersebar merata di daerah penelitian. Hasil penelitian menunjukkan bahwa nilai anomali gayaberat mikro antar waktu selang periode tersebut menunjukkan bahwa ada berberapa daerah yang mempunyai nilai anomali positip yang berkorelasi dengan kenaikan muka air tanah, anomali negatip berkorelasi dengan penurunan muka air tanah, dan nol tidak terjadi Perubahan apapun. Selanjutnya untuk memperoleh gambaran tentang dinamika muka air tanah, maka digunakan data gradien vertikal gayaberatmikro antar waktu dan anomalinya menunjukkan hasil sebagai berikut anomali gradien vertikal gayaberat mikro antar waktu bernilai negatip berarti terjadi penurunan muka air tanah, dan sebaliknya jika positip terjadi kenaikan muka air tanah. Hasil interpretasi 3D gaya berat mikro antar waktu dengan menggunakan perangkat lunak Gravblok menunjukkan beberapa daerah seperti Widoharjo dan sekitarnya, Perumahan Semarang sekitarnya, dan Perumahan Tlogosari sekitarnya telah mengalami intrusi air laut

Soil Vulnerability Levels based on Microtremor Data using the HVSR method in the Old City Area of Semarang

Kota Lama Semarang with the Dutch colonial era relics is currently used as a cultural heritage tourist spot. As a cultural heritage tourism place, it is necessarily aware of the potential for earthquake disasters due to active faults and volcanic eruptions, as well as the phenomenon of land subsidence caused by geological conditions of young alluvium. One of the geophysical techniques to determine subsurface structure is microtremor measurement. This study aims to determine vulnerability level based on dominant frequency, amplification, and seismic vulnerability index using HVSR analysis in Kota Lama area. Microtremor data measurement contained 11 points with a data retrieval duration of 30 minutes. The results of microtremor data analysis obtained dominant frequency values of 7.03 - 19.36 Hz, amplification of 0.72 – 3.7, and seismic vulnerability index of 0.074 – 0.95. Based on the parameters, it can be concluded that the Kota Lama Semarang area has a low level of vulnerability