INFLATION OF LONG VALLEY CALDERA, CALIFORNIA, BASIN AND RANGE STRAIN,AND POSSIBLE MONO CRATERS DIKE OPENING FROM 1990-94 GPS SURVEYS

Five years of annual Global Positioning System (GPS) surveys of a netw ork centered on Long Valley, California, constrain displacement rates for these stations relative. to a central station in the network. Thes e observations are consistent with recent models of resurgent dome inf lation in Long Valley (Langbein et al., 1995) and have sufficient sign al to detect the presence of Basin and Range strain in the Long Valley region. The data also allow for the possibility of dike inflation ben eath the Mono Craters; dike intrusion is consistent with the Mono Crat ers' recent geologic history of ash eruptions, with seismic tomography , leveling data, and geologic studies of these volcanic domes and flow s.