TY  - JOUR
PY  - 2017//
TI  - Trimming a hazard logic tree with a new model-order-reduction technique
JO  - Earthquake spectra
A1  - Porter, Keith
A1  - Field, Edward
A1  - Milner, Kevin
SP  - 857
EP  - 874
VL  - 33
IS  - 3
N2  - The size of the logic tree within the Uniform California Earthquake Rupture Forecast Version 3, Time-Dependent (UCERF3-TD) model can challenge risk analyses of large portfolios. An insurer or catastrophe risk modeler concerned with losses to a California portfolio might have to evaluate a portfolio 57,600 times to estimate risk in light of the hazard possibility space. Which branches of the logic tree matter most, and which can one ignore? We employed two model-order-reduction techniques to simplify the model. We sought a subset of parameters that must vary, and the specific fixed values for the remaining parameters, to produce approximately the same loss distribution as the original model. The techniques are (1) a tornado-diagram approach we employed previously for UCERF2, and (2) an apparently novel probabilistic sensitivity approach that seems better suited to functions of nominal random variables. The new approach produces a reduced-order model with only 60 of the original 57,600 leaves. One can use the results to reduce computational effort in loss analyses by orders of magnitude.<p />  <p>Language: en</p>
LA  - en
SN  - 8755-2930
UR  - http://dx.doi.org/10.1193/092616EQS158M
ID  - ref1
ER  -