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Kerentanan Pesisir Selatan KabupatenTulungagung Terhadap Gelombang Tsunami Berbasis Data Spasial Sonny Robert Dirgantoro; M. Ruslan; Emmy Sri Mahreda; Kissinger
SONDIR Jurnal Sondir
Publisher : Institut Teknologi Nasional Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36040/sondir.v4i2.3140

Abstract

Indonesia merupakan negara kepulauan yang dikelilingi dengan lempeng tektonik yang aktif dan selalu mengalami pergerakan. Sementara gunung api baik yang aktif maupun yang tidak aktif, sebagian besar terdapat di Pulau Sumatera dan Pulau Jawa. Beberapa kejadian gempa di Indonesia menimbulkan tsunami, tercatat kejadian gempa yang besar (7.8 Mw) tahun 1992 di Flores, Jawa Timur (7.8 Mw) tahun 1994, di Aceh 2004 (9.0 Mw), Nias (8.7 Mw) di tahun 2005, Pangandaran (7.7 Mw) dan Yogyakarta (5.9 Mw) di tahun 2006 diikuti dengan gelombang tsunami (Katalog Tsunami BMKG, 2018). Data tersebut, sejarah kegempaan di sebelah selatan Pulau Jawa tidak begitu banyak, dibandingkan dengan sebelah barat Pulau Sumatera, Sulawesi dan Maluku. Kabupaten Tulungagung, sebagian wilayah kecamatan yang terletak di sebelah selatanberbatasan langsung dengan laut terbuka, yaitu Samudera Hindia. Tercatat dalam sejarah, bahwa wilayah selatan Kabupaten Tulungagung terdampak oleh gelombang tsunami yang diakibatkan oleh gempa tektonik di selatan Kabupaten Banyuwangi pada tanggal 2 Juni 1994, yang pusatnya berada pada koordinat -10.48 LS dan 111.83 BT (usgs.gov). Gelombang tsunami menerjang pesisir selatan Kabupaten Tulungagung, di beberapa wilayah dengan tinggi gelombang yang variatif, tercatat gelombang tertinggi mencapai 4.8 meter di Pantai Popoh (usgs.gov). Metode yang digunakan dalam penelitian ini adalah memanfaatkan perangkat lunak Sistem Informasi Geografis (SIG) dengan menggunakan metode analisis weighted overlay untuk mendapatkan peta kerentanan gelombang tsunami dengan memasukkan parameter yang mempengaruhi kerentanan suatu wilayah terhadap gelombang tsunami (Diposaptono dan Budiman, 2006, dalam Seandy Firmansyah, IPB, 2012). Bobot untuk masing-masing parameter ditentukan dengan metode Analytical Hierarchy Process (AHP).
PENAPISAN SENYAWA FITOKIMIA DAN PENGUJIAN ANTIOKSIDAN EKSTRAK DAUN POHON MERAPAT (Combretocarpus rotundatus (Miq.) DARI HUTAN KERANGAS Kissinger; Evrizal AM. Zuhud; Latifah K; Darusman; Iskandar
Jurnal Penelitian Hasil Hutan Vol. 31 No. 1 (2013): Jurnal Penelitian Hasil Hutan
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20886/jphh.2013.31.1.9-18

Abstract

Kerangas forests typifies as tropical-rain vegetation trees, characterized by among others their low nutrients contents and sparse biodiversities, thereby denying their tree uses. The kerangas forests grow widespread in Kalimantan (e.g. South Kalimantan). Among the species that can grow and with stand such extreme condition is merapat (Combretocarpus rotundatus) trees. Their leaves contains particular chemical compounds that indicatively afford physiological bioactivities e.g. antioxidants. Consequentys this could expectedly emulate the added values for merapat tree uses. In relevant, scrutiny on phytochemical compounds and testing of such antioxidant efficacy were conducted on the samples of dry merapat tree-leaves taken from the kerangas forest in South Kalimantan. Initially, the dry leaves were extracted with methanol solvent, which yielded the methanol extract (i.e. sample 1), further fractionated by the column chromatography using chloroform eluant. The obtained chloroform-eluted fractions (sample 2) were fractionated again by the misced ethyl acetate-chloroform solvents (in equal proportion), which yielded the so-called sample 3. Phytochemical scrutiny revealed that the methanol extracts contained particular compounds such as flavonoids, phenol derivatives, bydroquinone, tannin, and triterpenoids, wich among them afforded the anticocidant efficacy. The methanol extract (sample 1) exchibited the very strongest antioxidant action by inflicting such reduction reaction on the free radicals released by the DPPH (2,2-diphenyl-1-picrylhydrazyl), while such action exerted by the chloroform-eluted fractions' sample 2 and the ethyl-acetate-chloroform-eluted fractions' sample 3 was very little. The inhibition of free-radical formation from DPPH as much as 50% (IC50) occurred at 21.82 ppm of the methanol-extract concentration. Meanwhile, vitamin C and BHT as the control antioxidants performed more efficiently at much less than 21.82 ppm (i.e. 6.74 and 6.28 ppm, respectively). However, such IC50 value strongly suggests that the merapat leaves' methanol extract afforded the potential bioactivity as antioxidant.