Seismic characterization of an active metamorphic massif, Nanga Parbat, Pakistan Himalaya

Citation
A. Meltzer et al., Seismic characterization of an active metamorphic massif, Nanga Parbat, Pakistan Himalaya, GEOLOGY, 29(7), 2001, pp. 651-654
Citations number
23
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
GEOLOGY
ISSN journal
0091-7613 → ACNP
Volume
29
Issue
7
Year of publication
2001
Pages
651 - 654
Database
ISI
SICI code
0091-7613(200107)29:7<651:SCOAAM>2.0.ZU;2-F
Abstract
Earthquakes recorded by a dense seismic array at Nanga Parbat, Pakistan, pr ovide new insight into synorogenic metamorphism and mass flow during mounta in building, Microseismicity beneath the massif drops off sharply with dept h and defines a shallow transition between brittle failure and ductile flow . The base of seismicity bows upward, mapping a thermal boundary with 3 km of structural relief over a lateral distance of 12 km, Anomalously low seis mic velocities are observed at the core of the massif and extend to depth t hrough the crust, The main locus of seismicity and low velocities correlate s with a region of high topography, rapid exhumation, high geothermal gradi ents, young metamorphic and igneous ages, and crustal fluid flow, We sugges t a genetic link between these phenomena in which hot reeks, rapidly advect ed from depth, are pervasively modified at relatively shallow levels in the crust,