The EDM measurement at the summit area of Merapi volcano had been done periodically in 1988, 1990, 1991, and 1992. By using the data of trilateration, horizontal strain components were calculated to evaluate strain pattern changes with time. During the period of 1988 - 1990, seismic and eruptive activities were rather low. In the period of 1990 - 1991, HFA and HFB type earthquakes increased and…
This paper reviews the times that silicic magmas related to major caldera systems spend in the crust prior to eruption. The significance of the time information is evaluated and combined with magma volumes and temperatures to quantify the mass and thermal fluxes associated to calderas.