Uplift, thermal unrest and magma intrusion at Yellowstone caldera

摘要

The Yellowstone caldera, in the western United States, formed ～ 640,000 years ago when an explosive eruption ejected ～ 1,000 km~3 of material. It is the youngest of a series of large calderas that formed during sequential cataclysmic eruptions that began ～16 million years ago in eastern Oregon and northern Nevada. The Yellowstone caldera was largely buried by rhyolite lava flows during eruptions that occurred from ～ 150,000 to ～ 70,000 years ago. Since the last eruption, Yellowstone has remained restless, with high seismicity, continuing uplift/ subsidence episodes with movements of ～ 70 cm historically to several metres since the Pleistocene epoch, and intense hydro-thermal activity. Here we present observations of a new mode of surface deformation in Yellowstone, based on radar interfero-metry observations from the European Space Agency ERS-2 satellite. We infer that the observed pattern of uplift and subsidence results from variations in the movement of molten basalt into and out of the Yellowstone volcanic system.