Continuous GPS Monitoring of Deformation at Kilauea Volcano During the Latter Half of the Pu`u `O`o eruption.
Abstract
The installation and development of a continuous Global Positioning System (GPS) network on Kilauea Volcano, Hawaii, has significantly improved the quality and resolution of deformation data for the volcano. The continuous GPS monitoring network of 17 stations on Kilauea was installed from 1995 onward in a collaborative project between the Crustal Deformation Group at Stanford University, the Hawaiian Volcano Observatory (HVO), and the University of Hawaii, Hilo. Continuous GPS measurements made on Kilauea between 1996 and 2001 show a long-term signal of nearly constant velocity with respect to the Pacific Plate. The horizontal component of velocity is characterized by south- to southeastward motion of all stations, with maximum rates of up to ~8 cm per year occurring on the south coast of Kilauea. The vertical component shows uplift of nearly 3 cm per year on the south flank and highlights an area of rapid subsidence (~4.5 cm per year) in the southernmost part of Kilauea's summit caldera. Combined with campaign GPS data from annual surveys made between 1990 and 1996, there is now a 12 year record of GPS for Kilauea. Using the new, high quality data set from the continuous GPS network we are able to model the deformation of Kilauea with greater confidence and to test and refine past models for deformation. For example, Owen et al. (2000) give a deformation model for Kilauea estimated from campaign GPS data. This model consists of two dislocations representing a basal decollement structure, two dislocations representing a deep rift system, and one point source for a summit magma chamber. We compare the predicted velocities from this model to the station velocities from the continuous GPS. Owen et al.'s model fits the recent data reasonably well, but there are significant disagreements. First, it fails to account for the uplift south of the east rift zone (indeed, it predicts subsidence). Second, it overestimates the amount of subsidence in the south caldera while also underestimating the horizontal velocities in the same area. Finally, their model does not well represent the velocities, both horizontal and vertical, at the stations located along the western and eastern edges of the network. Using non-linear optimization techniques, we have refined the details of Owen et al.'s model to see if the gross character of that model can be preserved without significantly violating the new continuous GPS data. Moreover, we have explored alternative, considerably simpler, deformation models that depart from the coupled decollement/deep rift zone hypothesis. Early results suggest that the simpler models, consisting of a single dislocation plane, can fit the data equally well. Owen, S., P. Segall, M. Lisowski, A. Miklius, R. Denlinger, and M. Sako, Rapid deformation of Kilauea volcano: GPS measurements between 1990 and 1996, J. Geophys. Res. 105, 18,983--18,998, 2000.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2002
- Bibcode:
- 2002AGUFM.V71A1252D
- Keywords:
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- 1243 Space geodetic surveys;
- 8020 Mechanics;
- 8494 Instruments and techniques