John C. Eichelberger

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Arc volcanoes often erupt andesite that appears to have been stored in reservoirs at shallow depth for protracted periods. As crystal-rich andesite is close in density to upper crust, such storage may be quite stable. Petrological evidence, and occasionally geological and geophysical evidence as well, suggests that the immediate trigger for eruption of the(More)
Using Synthetic Aperture Radar (SAR) interferometry, we detect several centimeters of uplift that accumulated during two years (1993-1995) around the vent of the New Trident volcano in Alaska's Katmai National Park. The areas of image coherence correspond to fresh, blocky lavas, while coherence is lost in ashcovered areas. From the uplift gradient we(More)
Figure 1. Generalized map of Karymsky and Academy Nauk. The 1996–2000 eruptive cycle started with simultaneous eruption of andesite from Karymsky summit vent and basalt from new vent formed in northern part of Academy Nauk caldera. ABSTRACT Calcic cores in plagioclase of Karymsky andesite of the 1996– 2000 eruptive cycle texturally and compositionally (both(More)
With the ending of the Cold War, the US Department of Energy is responsible for the remediation of radioactive waste and disposal of land no longer needed for nuclear material production or related national security missions. The task of characterizing the hazards and risks from radionuclides is necessary for assuring the protection of health of humans and(More)
Despite a V30 000 years difference in age, two caldera-forming eruptions at Karymsky volcanic center, Kamchatka ^ Karymsky (7900 yr BP) and Academy Nauk (ca. 40 000 yr BP) ^ produced two-pyroxene dacites with the same composition and mineralogy. Granophyric xenoliths of the identical whole-rock chemistry were found in basalts erupted within Academy Nauk(More)
The simultaneous eruption in 1996 of andesite from Karymsky volcano and of basalt from the Academy Nauk vent 6 km away appears to provide a case of mafic recharge of an andesite reservoir for which the time of recharge is exactly known and direct samples of the recharging magma are available. The explosive phreato-magmatic eruption of basalt was terminated(More)
Mafic to intermediate enclaves are evenly distributed throughout the dacitic 1991–1995 lava sequence of Unzen volcano, Japan, representing hundreds of mafic recharge events over the life of the volcano. This study documents the morphological, textural, chemical, and petrological characteristics of the enclaves and coexisting silicic host lavas. The eruptive(More)
s ............................................................................................................................. 37 Plenary Sessions: Extreme Events ..................................................................................... 39 The Oct-Nov 2002 Earthquake Sequence and the Denali Fault, Alaska ................................... 49(More)
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