The destructive earthquakes occurred in Sumatra are dominated by medium earthquakes, which generally come from the Sumatra fault and to have a direct impact on the land, buildings and around residential buildings. These earthquakes can be classified into high-frequency earthquakes with low-vibration periods. The hazards caused by the earthquake are mostly from damage and collapse of the residential buildings. This study is a literature review that aimed to observe the characteristics of rocks and ground in Sumatra areas based on b-value that obtained using seismicity estimation is related to the resistance of the earthquake on residential buildings. The b-values obtained from some previous researches so that they could be concluded, and then analyzed the type and condition of the local ground and then evaluated its effect on the surrounding buildings. Based on the outcomes, the estimation of b-value seismic parameters in Sumatra was found 0.34 to 0.5. It means that the type of ground in areas of Sumatra has a hard rock layer. Physically, it has highfrequency earthquake waves; low vibration periods, spreading efficiently on hard layer and having a direct impact on local buildings consequently the risk of collapse building will be higher.

Dalam pelaksanaan proyek konstruksi selalau ada potensi bahaya atau Risiko yang dapat menyebabkan kerugian. Setiap tempat kerja selalu memiliki Risiko kecelakan kerja yang dapat menggangu aktivitas pekerjaan dalam sebuah proyek. Faktor-faktor yang menyebabkan terjadinya kecelakaan kerja yang dapat mengganggu aktivitas pekerjaan dalam sebuah proyek. Oleh karena itu diperlukan suatu manajemen agar dapat mengatur jalannya proyek dengan baik, termasuk pula manajemen Risiko K3 (Kesehatan dan Keselamat Kerja). Tujuan dan sasaran manajemen risiko K3 (Kesehatan dan Keselamatan Kerja) adalah terciptanya system K3 (Kesehatan dan Keselamtan kerja) di tempat kerja melibatkan segala pihak sehingga dapat mencegah dan mengurangi kecelakaan dan penyakit akibat kerja dan terciptanya tempat kerja yang aman, efisien, dan produktif. Penelitian ini akan dilakukan identifikasi risiko K3, penilaian risiko K3, serta strategi pengendalian terhadap risiko K3 pada pekerjaan Pembangunan daerah irigasi (lanjutan). Dari hasil penelitian teridentifikasi 45 potensi risiko kecelakaan kerja yang dapat terjadi. Berdasarkan penilaian terhadapa Risiko K3 diketahui level masing-masing risiko yaitu terdapat 45 risiko tergolong Medium Risk dan dari 47 mengidentifikasi risiko terdapat 2 tergolong Low Risk. Pada penelitian ini perlu dilakukan penanganan yaitu dengan memberikan pengendalian risiko berupa penerapan K3 dilapangan meliputi penggunaan APD, rambu-rambu peringatan dan standarisasi pengaman pada saat bekerja di lapangan.

The coastal environment is an area that always changes. It depends on the power balance between topography, rocks, and its nature with tidal and wind waves. Progress in the Purus sub-district resulted in an increase in the amount of groundwater demand. If this happens, it can cause a drawdown so that the well water of the residents feels brackish or feels salty. This study aims to determine the salinity of shallow well water when viewed from the distance of the well to the coastline (x1) and groundwater level (x2) in Purus Padang Village. This type of research is field research (field research), using a quantitative approach. The sample was taken as many as 18 wells in Purus. The results showed that the salinity of well water occurred unevenly in Purus Village. If the distance of the well is further away from the coast, the salinity value will be lower. If the depth (height) of the water table is getting farther away from the sea level, the salinity value will be higher. For consumption, the salinity content in Purus Village is still within normal limits (<250 mg/l). The spread of salinity is caused by the flow of surface water.

The tendency of the recurring earthquake phenomenon in the same place in an area with a high seismic level has triggered an increase in earthquake activity in the region. Kabupaten Pesisir Selatan, which is located in West Sumatra Province, is a coastal area that is very close to the waters of the Sumatran sea as well as a source of destructive earthquakes that hit Sumatra. To anticipate the risk of future earthquakes and as an effort to increase public awareness and preparedness in the South Coast, in particular, it is necessary to provide understanding and knowledge of the seismic activities that have occurred there. The research method was carried out by collecting earthquake event data in the South Coast region for the period of January - December 2018 from the United States Geological Survey (USGS) data. The results of the analysis concluded, that in the Pesisir Selatan District there were frequent tectonic earthquakes, and also followed by landslides due to the contours of many hilly areas.

Rantai pasok adalah metode yang bertujuan untuk meningkatkan daya layan (serviceability) dalam menghasilkan suatu produk barang atau jasa kepada pengguna akhir dengan serangkaian proses produksi didalamnya. Metode ini diyakini telah membawa banyak manfaat dan sukses diterapkan di dalam industri manufaktur untuk kemudian diaplikasikan dalam industri lainnya termasuk pada industri konstruksi. Pengadopsian metode tersebut pada industri konstruksi bukan berarti tidak menimbulkan permasalahanpermasalahan baru. Oleh karena itu, diharapkan dengan adanya penelitian ini dapat memberikan gambaran lebih dalam mengenai praktik rantai pasok khususnya terkait risiko yang ditimbulkannya. Penelitian ini bertujuan untuk mengetahui tingkat risiko menggunakan matriks analisis probabilitas dan dampak, mendapatkan faktor risiko paling dominan menggunakan analisis faktor serta mengetahui hubungan antara tingkat risiko dengan faktor risiko dalam konteks rantai pasok proyek konstruksi. Penelitian dilakukan dalam bentuk survei persepsi risiko responden terhadap para pelaku dalam rantai pasok proyek konstruksi gedung yaitu kontraktor, subkontraktor, dan supplier di Kota Padang Sumatera Barat.