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Recent Emerged Reef Terraces of the Yenkahe Resurgent Block, Tanna, Vanuatu: Implications for Volcanic, Landslide and Tsunami Hazards

Chen Jeffrey K., Taylor Frederick W, Edwards Lawrence, Cheng Hai, Burr G. S. 1995. The Journal of Geology.
Recent Emerged Reef Terraces of the Yenkahe Resurgent Block, Tanna, Vanuatu: Implications for Volcanic, Landslide and Tsunami Hazards
ARTICLE, (1995 ) - PUBLISHEDVERSION - English (en-GB)
The Journal of Geology
OPENACCESS - .
Audience : RESEARCHERS
The University of Chicago
Subject
VOLCANOLOGIE, SISMOLOGIE
Domains
Géologie, Volcanologie
Description

Emerged reef terraces record the extraordinarily rapid Holocene uplift rate of the fault-bounded Yenkahe résurgent block (YRB), located within a partially submerged Quatemary caldera on Tanna Island, Vanuatu, southwest Pacifie. The presently active volcano, Yasur, is located at the western end of the YRB. Episodic uplift of the YRB is probably associated with the movement of magma below the Yenkahe area. A historically recorded uplift at Port Resolution Bay in a.d. 1878 raised the shoreline —15 m. This a.d. 1878 event was accompanied by a local earthquake and a tsunami that reached —12 m élévation. Coral samples from terraces at mean altitudes of 155 m and 15 m above présent sea level yield 230Th/234U dates of a.d. 1002 ± 10 and a.d. 186S ± 4, respectively. These âges imply a mean uplift of 156 mm/}! for the YRB since a.d. 1002 until a.d. 1992. This volcanically related uplift occurs within the context of régional uplift of the southem New Hébrides arc. The late Holocene uplift rate, —1 mm/yr, was determined from emerged terraces on the north and west coasts of Tanna. There hâve been several large volcanic éruptions in the geological history of Tanna; continued emplacement of magma at shallow levels below the YRB poses a possible volcanic hazard to the population there. Numerous faults in the wealdy consolidated YRB strata and relief created by rapid uplift increase the probability of hazards from landslides and tsunamis.

Keywords
Language
English (en-GB)
Creators
Chen Jeffrey K., Taylor Frederick W, Edwards Lawrence, Cheng Hai, Burr G. S
Contributors
Sources
The Journal of Geology Volume 103, Number 5 Sep., 1995
Coverage
Vanuatu, Tanna
Name of newspaper
The Journal of Geology