Auxiliary Material for
GPS constrained coseismic source and slip distribution of the 2013 Mw6.6 Lushan,
China, earthquake and its tectonic implications
Zaisen Jiang1, Min Wang2, Yanzhao Wang2, Yanqiang Wu1, Shi Che3, Zheng-Kang
Shen4, Roland Bürgmann5, Jianbao Sun2, Yonglin Yang6, Hua Liao6, and Qiang Li7
1. CEA Key Laboratory of Earthquake Prediction, Institute of Earthquake
Science, China Earthquake Administration, Beijing 100036, China
2. State Key Laboratory of Earthquake Dynamics, Institute of Geology, China
Earthquake Administration, Beijing 100029, China, Email:
mwang@gps.gov.cn
3. China Earthquake Administration, Beijing 100036, China
4. Department of Earth and Space Sciences, University of California, Los
Angeles, California 90095-1567, USA
5. Department of Earth and Planetary Science, University of California, Berkeley,
California 94720-4767, USA
6. Sichuan Earthquake Administration, Chengdu 610041, China
7. National Earthquake Infrastructure Service, China Earthquake Administration,
Beijing 100036, China
Geophysical Research Letters
Introduction
The auxiliary material contains additional text, seven figures and four tables that
supplement the main article.
1. txts01.pdf
The text file provides the details on GPS data collection and processing, uncertainty
estimation of uniform slip model, determination of uncertainty of a priori constraints
of distributed slip model, tests of fault shallow slip, and test of fault sinistral slip. The
two tables (Table S1 and Table S2 ) are included in the text.
2. figs1.tif
Figure S1. The statistics of GPS coordinate repeatability of daily solutions. (a) Before
the earthquake. (b) After the earthquake.
3. figs2.tif
Figure S2. Crustal structure model. The three panels show Vp, Vs, and density
profiles for the western Sichuan plateau and Sichuan basin respectively.
4. figs3.tif
Figure S3. Uncertainty estimation of the fault location and geometry parameters of
uniform slip model using F-test. Blue and red curves are the weighted postfit residual
χ2 values and corresponding confidence levels obtained from the F-test respectively,
as functions of the parameters being evaluated.
5. figs4.tif
Figure S4. (a) Trade-off curve between the total number of resolved parameters by
data and the weighted postfit residual χ2 of data. Numbers next to the crosses on the
curve denoting the corresponding uncertainty values for the smoothing constraints.
We choose the optimal uncertainty value on the trade-off curve which has the
minimum distance to the origin point measured after normalization of both the
resolution and χ2 values. (b) Slip distribution of a test model constrained using a
relatively relaxed smoothing with uncertainty of 0.500 m.
6. figs5.tif
Figure S5. The slip models for test. (a) Without the zero-slip constraints on the top
patches, and (b) Without the top three-layer of the fault plane.
7. figs6.tif
Figure S6. Rake angle vs. strike direction of fault plane from inversions of uniform
slip model (blue curve). The weighted postfit residual χ2 (red curve) shows the
optimal solution at the strike of N28°E.
8. figs7.tif
Figure S7. GPS velocity field in the vicinity of the Lushan earthquake. Two velocity
profiles are drawn across the Longmen Shan fault located north and south of the
Lushan segment. The normal and strike-slip components of the two profiles are
shown in the inset sketches, and extensional and dextral slips are positive. The black
arrow pairs on the fault segments indicate the senses of slip directions for the two
components, determined from the GPS data. Red and green data points in the sketches
are normal and strike-slip components and grey ones are sites whose displacements
are dominated by deformation around the Xianshuihe fault and not used for model
fitting. Gray curves are data fitting arctan functions whose widths denote the ranges of
uncertainty.
9. tabs03.docx
Table S3. Coseismic displacements: observations and model predictions
10. tabs04.docx
Table S4. Fault slip model