de Fuca Ridge at the "source site" of the 1993 eruption William Menke Lamont−Doherty Earth Observatory of Columbia University, Palisades NY 10964 USA Michael West Lamont−Doherty Earth Observatory of Columbia University, Palisades NY 10964 USA Maya Tolstoy Lamont−Doherty Earth Observatory of Columbia University, Palisades NY 10964 USA (07−December−01) ABSTRACT Seismic imaging reveals a shallow−c...

New and previously published micro-gravity data are combined with InSAR data, precise levelling and GPS measurements to produce a model for the processes operating at Krafla volcano, 20 years after its most recent eruption. The data have been divided into two periods: from 1990 to 1995 and from 1996 to 2003 and show that the rate of deflation at Krafla is decaying exponentially. The net micro-g...

Kashmar granitoids of Taknar zone, in north part of Lut block, intruded into volcanic rocks and consist of granites, granodiorites, monzodiorite and gabbrodiorites. They are composed of mainly plagioclase, alkali-feldspar, quartz, amphibole, biotite and pyroxene minerals. Harker diagram variation, including negative correlations CaO, MgO, FeO, TiO2 and V and positive correlations K2O, Rb, Ba, a...

[1] Volcanic SO2 can affect the Earth’s environment. Where no direct measurements of SO2 in the atmosphere are available, a petrologic method of assessing sulfur release from the magma must be used. However, in studies of arcderived eruptions, satellite-based measurements of SO2 emissions using Total Ozone Mapping Spectrometer (TOMS) data are orders of magnitude greater than those calculated pe...

[1] Fogo volcano, Cape Verde Islands, erupted in April 1995 after 43 years of dormancy. About 46 10 m of lava erupted during 7.5 weeks from vents on the SW flank of Pico do Fogo into Cha das Caldeiras. Interferograms obtained from 1993–1998 ERS SAR data show ground deformation due to the feeder dike but lack evidence for any volcano-wide deformation related to volume changes of a shallow magma ...

Older and younger granitoids are widespread throughout the basement rocks of NE Egypt. Therefore, they are played a significant role in the evolution of the Pan-African crust. The Wadi El Sheikh-Gabal Saint Katherine area comprise three distinctive magmatic granitoid suites, namely: (1) calc-alkaline older quartz monzodiorite-tonalite suite (COG), (2) calcalkaline younger monzogranite suite (CY...

Estimates of CO emissions at spreading centres, convergent margins, and plumes have been reviewed and upgraded 2 using observed CO r He ratios in magmatic volatiles, He content estimates in the magmatic sources, and magma 2 emplacement rates in the different tectonic settings. The effect of volatile fractionation during magma degassing, Ž . investigated using new rare gas and CO abundances dete...

We investigate the problem of estimating magma chamber geometry using InSAR observations of Sierra Negra volcano, Galápagos. Ascending and descending interferograms are combined to determine vertical and one horizontal component of displacement. The ratio of maximum horizontal to vertical displacement suggests a sill-like source. Spherical or stock-like bodies are inconsistent with the data. We...