Investigating earthquakes nucleation from the resposne of

Himalayan seismicity to the Monsoon

Thomas ADER, Kristel ChanardNadia LAPUSTA, and Jean-Philippe AVOUAC

December 9, 2011

TIBETINDIAGPS

LOADING OF THE INDIAN PLATEDUE TO THE MONSOON

NEPAL

earthquakes

Modified from Bettinelli et al. (2008)

GPS

GPS

TIBETINDIANEPAL

TIBETINDIA NEPAL

earthquakes

earthquakes

GPS

S

N

Seismicity

Montrer la serie GPS avec la prediction du modele de Kristel

Also periodic stress due to tidesC

oulo

mb

stre

ss

3kPa

time time2 stresses with roughly the same amplitude (~3kPa) but different periods but…

-No correlation of seismicity with tidal stress- Correlation with hydrological cycle (Monsoon)

• Nucleation is time dependent. • Nucleation predicted by rate-and-state friction

on finite size faults can explain our observations• The characteristic time for earthquake

nucleation (hence faults frictional properties) can be assessed:– long enough so that the response to earth

tides (12h) is damped– short that enough seismicity response to

seasonal variations of stress.

IMPLICATIONS FOR NUCLEATION