Publication Date:
2022-06-09
Description:
Newly acquired GPS data along transects across Himalaya in Eastern Himalayan Syntaxis (EHS) reveal a clockwise
rotation of rigid micro-plate comprising part of Brahmaputra valley, NE Himalaya and Northern Myanmar
that rotates about a pole located at 14.5°N, 100.8°E at an angular rate of 1.75 ± 0.12°/Myr. The EHS is being
torn-off from the main Indian Plate as a rigid block around which the kinematic clockwise rotation of Tibetan
GPS sites toward the Sichuan-Yunnan region occurs in the Eurasia fixed frame. The residual velocity field of
the newly acquired data estimated after removing the rotation that minimizes the GPS rates around EHS show
a clear NE motion of the EHS sites, indentation of the rigid Indian plate into a less rigid area of the Eurasian
plate. Themost extensive EHS zones of compression and shortening are in the direction of indenter convergence,
with average values ranging between ~50–100 nanostrain/year. Along the frontal segment of EHS, from NWto
SE, the shortening rate is reduced from the local maximum value of 160 to ~80 nanostrain/year, thus indicating
a possibly locked fault patch of Mishmi or Lohit thrusts, the southernmost part of segment activated during the
large 1950 Assam earthquake, Mw 8.6.
An elastic block-model was invoked to infer the average slip rates of sections around EHS and to estimate an average
locking depth of ~15 km. The slip rate perpendicular to the locked sector of EHS reaches 32.4mm/year and
permits to roughly infer a recurrence time of ~200 year for an earthquake as energetic as the 1950 Assam event.
Description:
Published
Description:
15-26
Description:
1T. Deformazione crostale attiva
Description:
JCR Journal
Keywords:
GPS data
;
Eastern Himalayan Syntaxis (EHS)
;
India plate
;
Block modeling
;
strain rate
;
locked fault
;
Crustal deformation
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Permalink