Publication Date:
2022-03-16
Description:
Several methods such as paleoseismic trenching, mapping of offset geomorphic markers, and dating of
scarp profiles have been used to determine slip rates of normal faults in the central Apennines.
Combining measurements obtained with different methods remains challenging because non-tectonic
processes can introduce noise or spurious signals that are elusive to quantify, and these influence slip
rate estimates. To this end, we meta-analyzed throw measurements with associated ages collected in
the central Apennines with several methods to quantify such erratic fluctuations and method-related
variances.
We show that throw rates are overdispersed with respect to nominal uncertainties in throw and age;
therefore, they are commonly affected by unmodeled noise processes. After comparing throw rate
distributions sampling the same faults with different techniques, no clear spatiotemporal patterns
appear, but only quasi-random noise. Assuming that field investigators sampled real tectonic features
(i.e., fault scarps), we find that such erratic throw rates indicate total uncertainties are two to three
times greater than the stated observation uncertainties. In this situation, a simple and robust null
hypothesis is appropriate. We propose that most faults should be assumed to have uniform throw rate
along their traces, except for possible tapering near unconnected ends. We also propose that models in
which throw rates are time-dependent (within the last 25 ka) are not yet justified. Then, relying on the
estimated total uncertainties, we determine the most probable long-term fault throw rate for each
active fault by combining different throw-rate probability density functions.
Description:
Published
Description:
e2021JB023252
Description:
2T. Deformazione crostale attiva
Description:
JCR Journal
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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