Deformation of the Northwestern Okhotsk Plate: How is it happening?
Other literature type
(issn: 1868-4564, eissn: 1868-4564)
The Eurasia (EU) – North America (NA) plate boundary zone across Northeast
Asia still presents many open questions within the plate tectonic paradigm.
Constraining the geometry and number of plates or microplates present in the
plate boundary zone is especially difficult because of the location of the
EU-NA euler pole close to or even upon the EU-NA boundary. One of the major
challenges remains the geometry of the Okhotsk plate (OK). whose northwestern
portion terminates on the EU-OK-NA triple junction and is thus caught and
compressed between converging EU and NA. We suggest that this leads to a
coherent and understandable large scale deformation pattern of mostly
northwest-southeast trending strike-slip faults which split Northwest OK into
several extruding slivers. When the fault geometry is analysed together with
space geodetic and focal mechanism data it suggests a central block which is
extruding faster bordered east and west by progressively slower extruding
blocks until the OK plate boundary faults are encountered. Taking into
account elastic loading from both the intra-OK faults and the OK-Pacific (PA)
boundary reconciles geodetic motions with geologic slip rates on at least the
OK-NA boundary which corresponds to the Ulakhan fault.