This study used a qualitative approach and the type of research conducted is descriptive. Taking the subjects of this study were 33 students of class IX SMP Negeri 16 Bandung academic year 2017/2018. Based on the results of data analysis shows that no students can answer correctly all the questions that have been given. Based on data analysis, it can be concluded that reading error 13.0%, comprehension 3.7%, transformation 12.2%, skill 9.7%, writing final answer 16.3% and carelessness 7.7%, errors done by students include: Newman's procedure is reading errors, comprehension errors, transformation errors, process skills errors, and errors in encoding errors and careless errors. The cause factor is not able to compose the meaning of the word thought into the form of a sentence matamatika, not understand the questions asked, less thorough, less able to capture information problems contained in the problem, forgot, lack of practice working on various story form problems.
Overexploitation in 1980-2000 caused a lot of groundwater loss in the aquifer coastal of Bandar Lampung. Groundwater has been degraded with increasing salinity due to the intrusion of seawater. In 2013, the intrusion extended 400 m from the coastline. Subsurface geological mapping is carried out to examine alluvial formation’s material constituents and the ability to transfer seawater to land. Three well explorations combined with three geoelectric tomography and 51 points of gravity. The gravity method is used to map structures that can connect coastal aquifers and land aquifers. Meanwhile, geoelectric tomography to map the presence of aquifers and low resistivity zones by seawater intrusion. The coastline has relatively shallow aquifers at a depth of 2-10 m in a sand layer with coral inserts, while the lower part is composed of silt and clay. The aquifer has experienced a decrease in resistivity of fewer than 10 ohms.m appears in the three circular patterns, caused by seawater. In addition to the permeable zone of shallow aquifers, there is a northwest-southeast trending structure that can channel seawater to land aquifers.
Tsunami Selat Sunda yang terjadi pada akhir tahun 2018 akibat deformasi (longsor) Gunung Anak Krakatau (GAK) tidak memiliki Early Warning System (EWS) yang memadai bahkan tidak terdeteksi oleh seismogram dengan jelas. Peristiwa itu menunjukkan bahwa pemantauan deformasi GAK sangat diperlukan. Penelitian ini bertujuan untuk mengetahui proses deformasi GAK sebelum tsunami menggunakan metode DInSAR. Metode ini memanfaatkan perbedaan dua fase atau lebih citra SAR dengan akuisisi yang berbeda untuk memperoleh topografi dan deformasi. Data yang digunakan adalah sepasang citra Sentinel-1 yang diakuisisi pada periode 7-19 Desember 2018. Penelitian ini berhasil menunjukkan GAK telah mengalami deformasi beberapa hari sebelum tsunami Selat Sunda pada 22 Desember 2018 terjadi. Nilai deformasi GAK pada periode ini sebesar -0.12 sampai 0.04 meter relatif terhadap Line of Sight (LOS). Hasil tersebut menunjukkan deformasi yang terjadi mencakup 94 Ha luas area GAK dengan ± 32,036 m 3 material vulkanik yang bergerak dominan ke arah barat daya. Volume material yang cukup banyak ini tidak menghasilkan tsunami, diperkirakan karena periode pergerakan tersebut terjadi secara perlahan/tidak seketika yaitu pada rentang 12 hari. Material longsoran tertumpuk dan menjadi tidak stabil, kemudian terjadi longsoran serentak yang kemungkinan dipicu oleh banyaknya aktivitas vulkanik GAK akhirnya memicu terjadinya tsunami pada 22 Desember 2018. Temuan ini menunjukkan bahwa citra SAR mampu mengidentifikasi adanya pergerakan massa pada lereng GAK sebelum tsunami terjadi, sehingga dapat digunakan untuk monitoring permukaan GAK sebagai sistem peringatan dini pada deformasi yang berpotensi menyebabkan tsunami di kemudian hari.
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