A multi-task deep learning scheme using receiver functions to study
crustal tectonics and its application to the middle-southern segment of
Tanlu Fault Zone and adjacencies
Abstract
We propose a novel scheme that applies a multitasking convolutional
neural network to learn the back azimuthal behavior from receiver
function seismograms, which can effectively predict the depth and
occurrence of the Moho beneath a single seismic station. Our scheme
consists of three main steps: 1. Based on the style transfer technique,
we generate 9000 synthetic receiver function seismograms blended by
realistic noise as training data sets. 2. A multitasking convolutional
neural network is trained to predict the depth and occurrence of the
Moho. 3. All real receiver function seismograms are reconstructed by the
accelerated joint iterative method before prediction. We apply the
scheme to study the middle-southern of the Tanlu fault zone and adjacent
regions and successfully achieve the depth and occurrence of the Moho
beneath 10 permanent seismic stations. The predicted depths are in
agreement with the results computed by conventional methods, and the
predicted strikes and dip angles present an undulating Moho with near
NE-striking. Moreover, the predicted strikes are nearly consistent with
the strikes of the normal faults in the upper crust, which implies that
intense continental extension in the Cretaceous play a prominent role in
the tectonic deformation of the brittle upper crust and the ductile
lower crust simultaneously. Besides, it helps to illustrate that the
stress field orientation of the major geological event can be recorded
and preserved in the lower crust.