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Supplementary Materials for
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Coupling of Hawaiian volcanoes only during overpressure condition
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Manoochehr Shirzaei1,3, Thomas R. Walter2 & Roland Bürgmann3
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Correspondence: shirzaei@asu.edu, Tel: +1 480 727 4193, fax: +1 480 965 8102
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Telegrafenberg, D – 14473 Potsdam, Germany
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USA
School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-6004,
Section 2.1, Dept. Physics of the Earth, GFZ German Research Center for Geosciences,
Department of Earth and Planetary Science, University of California, Berkeley, California,
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GPS data analysis
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In this study GPS data are only used to validate the InSAR results. The network is operated
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by Hawaiian Volcano Observatory and University of Hawaii and the data is provided by the
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UNAVCO Facility with support from the National Science Foundation (NSF) and National
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Aeronautics and Space Administration (NASA) under NSF Cooperative Agreement No.
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EAR-0735156. The locations of the GPS stations that are continuously observed during the
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period of 2003- 2008 are shown in Figure (S1). We use the Bernese 5 software [Dach et al.,
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2007] to solve the daily coordinate of the GPS stations in ITRF2005 reference frame. The
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precise orbit data are obtained from IGS. To generate a time series of the displacement field
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for each GPS station we use a Kalman Filter [Hofmann-Wellenhof et al., 2000]. In Fig. S3
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each GPS displacement sample is the average coordinate of the station within 3 days that
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temporally spans the InSAR observation point and was projected into the satellite LOS for
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comparison with the InSAR time series.
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References
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Dach, R., U. Hugentobler, P. Fridez, and M. Meindl (2007), Bernese GPS Software Version
5.0, 640 pp., Astronomical Institute, University of Bern, Bern.
Hofmann-Wellenhof, B., H. Lichtenegger, and J. Collins (2000), Global Positioning
System, Theory and Practice, 5th Edition, 390 pp., Springer, New York.
McTigue, D. F. (1987), Elastic stress and deformation near a finite spherical magma body:
resolution of the point source paradox, J. Geophys. Res., 92, 12931–12940.
Okada, Y. (1985), Surface deformation due to shear and tensile faults in a half-space, Bull.
Seism. Soc. Am., 75, 1135-1154.
Owen, S., P. Segall, M. Lisowski, A. Miklius, R. Denlinger, and M. Sako (2000), Rapid
deformation of Kilauea Volcano: Global Positioning System measurements between 1990
and 1996, J. Geophys. Res., 105(B8), 18,983–918,998.
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Table S1: The initial bounds for dislocation source parameters
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Parameter
Lower bound
Upper bound
Coordinates (km)*
Rift trace – 5
Rift trace + 5
Bottom Depth (km)
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Width (km)
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Dip (deg)
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110
Depth (km)
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Radius (km)
0.1
Depth lower bound
Horizontal location (km)
Location of maximum deformation - 5
6 Rift dikes
2 Magma
Location of maximum deformation
chambers
+5
Coordinates (km)
Rift trace – 10
Rift trace + 10
1 Basal
Depth (km)
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decollement
Width (km)
10
30
Dip (deg)
-10
10
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Fig. S1: Study area and data sets. The location of the Big Island with respect to other
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Hawaiian Islands is shown in the inset and the boundary of various volcanic systems are
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outlined. Dashed lines indicate the extent of rift zones of the volcanoes. Recent eruptive
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activity of Mauna Loa and Kilauea occurred both in the summit caldera region and along
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the rift zones. The trace of the SAR scene and the location of the stations of the GPS
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network are shown.
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Fig. S2: InSAR deformation time series. Spatiotemporal evolution of the deformation field
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over Hawaii Island obtained by InSAR time series. Each image presents the cumulative
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displacement since the beginning of the time series. For better illumination the color-scale
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is saturated beyond -10 cm (i.e. away from satellite) and +10 cm (i.e. toward the satellite).
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Fig. S3: a-i) InSAR deformation validation. Comparison between 3D cGPS time series
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projected into the line of sight (red dots) and InSAR time series (black dots). j)
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Quantitative evaluation of the difference between InSAR and cGPS data sets for each
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station in terms of root mean square error (RMSE).
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Fig. S4: Initial configuration of the deformation sources at Hawaii used for inverse
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modeling. The model comprises an analytical solution for uniform opening (rift) and slip
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(decollement) on rectangular dislocation planes[Okada, 1985] and volume change of finite
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spherical sources[Mctigue, 1987] in an elastic half-space medium.
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Fig. S5: The time series of the deformation source strengths for volcanic sources (a) and
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tectonic decollement slip (b). Shown are the volumetric changes of the rift zones, magma
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chamber and basal decollement. The obtained rate for decollement slip compares quite well
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with what was found in earlier GPS studies of south flank deformation [Owen et al., 2000].
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Fig. S6: a) Misfit (observed - modeled) time series and the associated RMSE. b) The
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spatiotemporal distribution of the misfit for the whole InSAR time series. The areas of the
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data points, which are not used in the modeling, are masked out. The large misfit in the
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2007/7/30 image might be due to unmodeled displacement at the eastern rift caused by
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intrusion during the 2007 Fathers Day episode but also includes remnant artifacts to the
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north of the rift zone.
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Fig. S7: Background seismicity for the period 2003-2008. a) 3D distribution of seismicity
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for Island of Hawaii. Events are color coded by event year. b) Temporal and spatial
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distribution of seismicity as a function of distance from Mauna Loa. c) Cumulative number
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of deep earthquakes (> 20 km) in a circle of 10x10km area around the central caldera at
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Mauna
Loa
and
Kilauea.
Seismicity
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(http://earthquake.usgs.gov/monitoring/anss/).
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data
courtesy
ANSS