Open AccessSeismic moment release during slab rupture beneath the Banda Sea
Author(s) -
Sandiford Mike
Publication year - 2008
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.2008.03838.x
Subject(s) - slab , geology , seismology , seismic zone , front (military) , stress field , induced seismicity , geophysics , oceanography , finite element method , physics , thermodynamics
SUMMARY The highest intermediate depth moment release rates in Indonesia occur in the slab beneath the largely submerged segment of the Banda arc in the Banda Sea to the east of Roma, termed the Damar Zone. The most active, western‐part of this zone is characterized by downdip extension, with moment release rates (∼10 18 Nm yr –1 per 50 km strike length) implying the slab is stretching at ∼10 −14 s −1 consistent with near complete slab decoupling across the 100–200 km depth range. Differential vertical stretching along the length of the Damar Zone is consistent with a slab rupture front at ∼100–200 km depth beneath Roma propagating eastwards at ∼100 km Myr –1 . Complexities in the slab deformation field are revealed by a narrow zone of anomalous in‐plane P ‐axis trends beneath Damar, where subhorizontal constriction suggests extreme stress concentrations ∼100 km ahead of the slab rupture front. Such stress concentrations may explain the anomalously deep ocean gateways in this region, in which case ongoing slab rupture may have played a key role in modulating the Indonesian throughflow in the Banda Sea over the last few million years.