Report of GPS-99 Session 6
Space and Terrestrial Techniques for Advanced crustal Deformation Research

Session 6-1: Crustal Movements and Seismic Events

Papers presented during this session spanned a wide range of topics, and all parts of the globe. There were papers discussing deformation in: Tokai, Japan; California, USA; Kyushu, Japan; Maharashtra, India; Aswan, Egypt; Nicoya, Costa Rica; Cairo, Egypt; Kozu Island, Japan; and Kinki, Japan, as well as several theory papers.

There were 10 planned oral presentations and 15 posters. Prior to the start of the meeting, one oral presenter cancelled and a poster presenter was given an oral time slot. In addition, two oral papers failed to appear at the time of their talk; and, several poster presenters failed to appear. So, in summary, the session consisted of 8 oral presentations, and about one dozen posters.

The meeting room was ideally sized for the audience. The room was comfortably full for the entire session. That is, there was sufficient space that late-comers could find a seat; but not so big that it seemed deserted. Average attendance during the session was about 140 people.

William Prescott

Section 6-2: Volcanic Events, Vertical Movements, et al.

The papers in this session were focused on observations and interpretations of vertical crustal deformations using InSAR and GPS. Most of the session was focused on volcanic deformation with a number of presentations related to earthquake deformation, plate boundary deformation, Earth rotation, and ocean loading. The results presented included observations over very short time periods of a few hours to several years and demonstrated how GPS can be used as a high temporal resolution observing technique both after the fact and in near real-time.

Spectacular results of volcanic deformation from volcanoes in Hawaii, Indonesia, Japan, and the Galapagoes showed how GPS and InSAR observations are being widely used for detecting the patterns of deformation around volcanoes. Many of these interferopgrams had large, symmetric signals that were interpreted with respect to Mogi source models. However, a number of the volcanoes had more complex deformation patterns indicative of greater spatial and temporal complexity in the shapes of the sources, their locations and evolutions, and the development of the volcanic edifices.

The large information content in these space geodetic data sets holds promise for increasing our understanding of volcanic systems and for the routine inclusion of these types of data in monitoring programs. The papers presented showed the complimentary nature of the two space geodetic techniques, GPS and InSAR, when they are integrated for source determination and highlighted their strengths for volcanic hazard assessments.

Frank Webb

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Session 6
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