A Kinematic Fault Network Model for Crustal Deformation

(including seismicity of optimal locking depth, shallow surface creep and geological constraints)

Yuehua Zeng and Zhengkang Shen

Elastic dislocation theory

Locked near the surface.

Slip at constant ratebelow transition depth

LockingDepth

For a given slip distribution on all the faults, the ground deformation vector at any point is obtained by taking a spatial convolution of the static point source Green's function with the fault slip function:

where m is the shear modulus, ni is a unit vector normal to the fault, Duj is the j-th component of slip on the fault, and Gni is the Green's function calculated from receiver to source. x is a vector describing the receiver location and x is a vector describing the corresponding source point where the Green's function is calculated.

1) assuming fault segments slip at certain rates beneath a locking depth2) locking depths are defined by local seismicity depth distributions3) slip vector conservation imposed at fault nodes or intersections4) depth dependent aseismic creeps

)1(),(

)(),(

D d

xGutxu

j

nijin x

xxnm

GPS only

With geological constraints geological rates

Comparison of geodetic and seismicity locking depth

UCERF 3 Testing Block model

(with/without seismicity depth, shallow surface creep and geological constraints)

Fixed depth of 15 km, no creep, no geological constraints

Seismicity depth, no creep, no geological constraints

Seismicity depth, creep, geological constraints

Fixed depth of 15 km, no creep, no geological constraints

Seismicity depth, no creep, no geological constraints

Seismicity depth, creep, geological constraints

Fixed depth, no creep, and no geological constraints

Seismicity depth, no creep, and no geological constraints

Seismicity depth, creep, and geological constraints

Fixed depth of 15 km, no creep, no geological constraints

Seismicity depth, no creep, no geological constraints

Seismicity depth, creep, geological constraints

UCERF 2 Model and Its Comparison with the Testing Block model

(both with seismicity depth, shallow surface creep and geological constraints)