| Penulis/Author |
Audrey Faral (1) ; Lavigne, Franck (2); Dr. Bachtiar Wahyu Mutaqin, S.Kel., M.Sc. (3); Fatima Mokadem (4); Rahim Achmad (5); Rohima Wahyu Ningrum (6); Pierre Lahitte (7); Dr. Danang Sri Hadmoko, S.Si., M.Sc (8); Dr. Estuning Tyas Wulan Mei, M.Si., M.Sc. (9) |
| Abstrak/Abstract |
Studying past eruptions gives a unique opportunity to understand volcanic hazards, particularly in Indonesia, where volcanic eruptions occur every year. As part of a recent approach to identifying and characterizing past volcanic events, we present the first reconstruction of the eruptive history of the Ternate and Tidore Islands (North Maluku, Indonesia) for the last 22,000 years cal. BP. This multidisciplinary study (geomorphology, tephrochronology, sedimentology, geochronology, geochemistry) aims to make the first stratigraphic and chronological continuum from the volcanic deposits found on a set of fifteen sections established in Ternate, Tidore, and Maitara Islands. Sedimentological and geochemical data from tephrostratigraphy studies suggest that these islands experienced at least four major explosive events from c. 22,000 to 740 years cal. BP. Paleosols radiocarbon dating and tephra geochemistry reveal a Plinian caldera-forming eruption of Telaga volcano on Tidore Island at c. 22,000 – 17,500 cal. BP. A second pumiceous eruption dated at c. 18,000 cal. BP is attributed to Gamalama volcano on Ternate and seems to be the last Plinian eruption of this volcano, whose current eruptive activity is mainly strombolian or phreatomagmatic. A succession of pyroclastic deposits of phreatomagmatic origin is related to the Ngade maar formation on Ternate Island, and the abundant deposits of scoria, pumice, and ash found on all sites probably occurred c. 14,500 - 13,000 cal. BP. No eruptions of the Kie Matubu volcano on Tidore Island have been reported by human beings since their presence in the region from the 16th century, but this study highlights two late Holocene eruptions, c. 2,500 cal. BP and 740 cal. BP. This first chronostratigraphic framework of the major eruptive events taking place in this region from the end of the Pleistocene provides valuable lessons on paleo-eruptive events and apprehends the potential present and future eruptive disasters on these vulnerable small volcanic islands. |
