Age determination of paleotsunami sediments around Lombok Island, Indonesia, and identification of their possible tsunamigenic earthquakes  

作　　者：Aswan Yahdi Zaim Yan Rizal I.Nyoman Sukanta Suci Dewi Anugrah Agus Tri Hascaryo Indra Gunawan Tatok Yatimantoro Weniza Hidayanti Purnomo Hawati Wahyu Dwijo Santoso Nurochim 

机构地区：[1]Geology Department, Institute of Technology Bandung (ITB),J1. Ganesha 10, Bandung 40132, Indonesia [2]Tsunami Mitigation Division - Meteorological Climatologicaland Geophysical Agency (BMKG), J1. Angkasa 1 no 2Kemayoran, Jakarta 10720, Indonesia

出　　处：《Earthquake Science》2017年第2期107-113,共7页地震学报（英文版）

摘　　要：Age determination of paleotsunami sediment from Lombok Island, Indonesia, and surrounding area has been carried out using the 210 Pb method in BATAN Jakarta. The basic theory of this method assumes that weathering of sediments, including paleotsunami sediments, will result in 210 Pb enrichment. The principle of this method is to calculate 210 Pb contents accumulation in a particular sedimentation interval from the surface to the deeper buried sediments. The results are then converted into age or depositional time in years ago unit. The dating results from the paleotsunami sediments of the Gawah Pudak（S8°46’2.91’’, E115°56’34.23’’） and Gili Trawangan areas（S8°21’1.38’’, E116°2’36.6’’） indicate the Gawah Pudak sediments were deposited 37 years ago（c. in 1977）and 22 years ago（c. in 1992）. Three paleotsunami sediments from Gili Trawangan were deposited 149 years ago（c. in 1865）, 117 years ago（c. in 1897） and 42 years ago（c. in 1972）. These results are then compared to the available Indonesian earthquake catalogue data. This study reveals that paleotsunami sediments around Lombok Islands, from older to younger, were caused by the 1857 earthquake（epicentre in Bali Sea; M7; S8°00’09.45’’,E115°29’56.41’’）, 1897 earthquake（epicentre in Flores Sea;M5.5; S6°47’59.62’’, E120°48’03.5’’ or Sulu Sea earthquake; M8.5; 70 km NW of Basilan Island）, the 1975 earthquake（Nusa Tenggara; S10°6’16.61’’, E123°48’09.39’’）, 1977 earthquake（in Waingapu, Sumba; M8.0;S11°5’39.34’’, E118°27’50.86’’） and the 1992 earthquake（Flores; M7.8; S8°28’52.11’’, E121°53’44.3’’）.Age determination of paleotsunami sediment from Lombok Island, Indonesia, and surrounding area has been carried out using the 210 Pb method in BATAN Jakarta. The basic theory of this method assumes that weathering of sediments, including paleotsunami sediments, will result in 210 Pb enrichment. The principle of this method is to calculate 210 Pb contents accumulation in a particular sedimentation interval from the surface to the deeper buried sediments. The results are then converted into age or depositional time in years ago unit. The dating results from the paleotsunami sediments of the Gawah Pudak（S8°46’2.91’’, E115°56’34.23’’） and Gili Trawangan areas（S8°21’1.38’’, E116°2’36.6’’） indicate the Gawah Pudak sediments were deposited 37 years ago（c. in 1977）and 22 years ago（c. in 1992）. Three paleotsunami sediments from Gili Trawangan were deposited 149 years ago（c. in 1865）, 117 years ago（c. in 1897） and 42 years ago（c. in 1972）. These results are then compared to the available Indonesian earthquake catalogue data. This study reveals that paleotsunami sediments around Lombok Islands, from older to younger, were caused by the 1857 earthquake（epicentre in Bali Sea; M7; S8°00’09.45’’,E115°29’56.41’’）, 1897 earthquake（epicentre in Flores Sea;M5.5; S6°47’59.62’’, E120°48’03.5’’ or Sulu Sea earthquake; M8.5; 70 km NW of Basilan Island）, the 1975 earthquake（Nusa Tenggara; S10°6’16.61’’, E123°48’09.39’’）, 1977 earthquake（in Waingapu, Sumba; M8.0;S11°5’39.34’’, E118°27’50.86’’） and the 1992 earthquake（Flores; M7.8; S8°28’52.11’’, E121°53’44.3’’）.

关 键 词：Age Paleotsunami Sediment ^（210）Pb Earthquake 

分 类 号：P315[天文地球—地震学] P597[天文地球—固体地球物理学]