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"Penelitian ini bertujuan untuk menganalisis fenomena amplifikasi gerak tanah gempa untuk Universitas Indonesia (Depok). Amplifikasi gerak tanah gempa merupakan peristiwa perbesaran gerakan tanah saat terjadinya gempa bumi akibat berbagai faktor geologi, termasuk sifat mekanik tanah dan karakteristik geoteknik. Metode penelitian yang digunakan meliputi: analisis data hasil pencatatan gempa, pemodelan satu dimensi (1D) dengan perangkat lunak DEEPSOIL v7, serta analisis komparatif terhadap hasil pencatatan gerak tanah gempa di permukaan tanah Hutan UI dan FMIPA UI. Hasil penelitian menunjukkan bahwa pemodelan secara nonlinear memberi akurasi yang lebih baik dibandingkan ekuivalen linear. Selain itu, perubahan stratigrafi akan berdampak signifikan bagi amplifikasi gerak tanah gempa. Studi ini juga mengidentifikasi hubungan antara variasi muka air tanah dan variasi nilai overconsolidation ratio (OCR) terhadap amplifikasi gerak tanah gempa yang terjadi.

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This research aims to analyze the phenomenon of seismic ground motion amplification for the University of Indonesia (Depok). Seismic ground motion amplification is the phenomenon of increased ground motion during an earthquake due to various geological factors, including soil mechanical properties and geotechnical characteristics. The research methods used include: analysis of earthquake recording data, one-dimensional (1D) modeling using DEEPSOIL v7 software, and comparative analysis of recorded seismic ground motion at the Hutan UI and FMIPA UI surface sites. The research results show that nonlinear modeling provides better accuracy compared to equivalent linear modeling. Additionally, changes in stratigraphy have a significant impact on seismic ground motion amplification. This study also identifies the relationship between variations in groundwater levels and variations in the overconsolidation ratio (OCR) with respect to seismic ground motion amplification."

"Tingginya intensitas atau frekuensi kejadian gerakan tanah atau tanah longsor di Jawa Tengah terlebih di Kabupaten Cilacap yang merupakan salah satu wilayah dengan frekuensi kejadian longsor yang tinggi maka diperlukan adanya upaya mitigasi bencana yang tepat untuk mengurangi resiko bencana. Sejak tahun 1998-2023 terdapat 303 kejadian gerakan tanah, data tersebut dibagi menjadi 70% data training dan 30% data testing (validasi). Sebagai upaya mitigasi, diperlukan adanya kajian terkait analisis persebaran zona rawan longsor. Kajian tersebut mencakup identifikasi faktor penyebab tanah longsor melalui metode frequency ratio dan statistical index. Faktor penyebab gerakan tanah terdiri dari tingkat kemiringan lereng, elevasi, aspek lereng, intensitas curah hujan, jenis penutup lahan, tipe litologi, kerapatan sungai utama dan anak sungai, kerapatan jalan, kerapatan kelurusan, dan data kejadian longsor. Tujuan Frequency ratio yaitu mengokorelasikan kejadian gerakan tanah dengan faktor kausatif terkait dan Statistical index dapat memberikan bobot korelasi faktor tersebut terhadap kejadian gerakan tanah. Analisis dengan kedua metode tersebut dapat memperkuat interpretasi terkait pengaruh parameter gerakan tanah terhadap kejadian gerakan tanah. Kemudian akan dilakukan uji validasi melalui analisis Grafik AUC. Pada penelitian ini, hasil analisis frequency ratio bernilai AUC 84,9 dan hasil analisis statistical index sebesar 81,5. Kedua nilai tersebut termasuk kategori baik. Sehingga diperoleh bahwa faktor penyebab gerakan tanah di Cilacap dominan dipengaruhi oleh litologi batuan, tingkat kemiringan lereng, elevasi dan aspek lereng.

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The high intensity or frequency of land movement or landslides in Central Java, especially in Cilacap Regency, which is one of the areas with a high frequency of landslides, means that appropriate disaster mitigation efforts are needed to reduce disaster risk. From 1998-2023 there were 303 ground movement incidents, the data was divided into 70% training data and 30% testing (validation) data. As a mitigation effort, a study is needed regarding the analysis of the distribution of landslide-prone zones. The study includes identifying factors that cause landslides using frequency ratio and statistical index methods. Factors causing land movement consist of slope level, elevation, slope Aspect, rainfall intensity, land cover type, lithology, density of main river network and tributary, density of road network, Lineament density, and data on landslide events. The purpose of the Frequency ratio is to correlate ground movement events with related causative factors and the Statistical index can provide a weight for the correlation of these factors with ground movement events. Analysis using these two methods can strengthen interpretations regarding the influence of ground motion parameters on ground motion events. Then a validation test will be carried out through AUC graph analysis. In this study, the results of the frequency ratio analysis were AUC 84.9 and the results of the statistical index analysis were 81.5. Both values are in the good category. So it was found that the factors causing land movement in Cilacap were predominantly influenced by rock lithology, slope level, elevation and slope aspect."