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Global Volcanism Program | Image GVP-03296

The NE caldera wall of the 17 x 32 km Long Valley caldera, seen from Lookout Mountain on the west, forms a curved ridge that rises more than 1 km above the caldera floor.  The caldera was formed following the eruption of the voluminous Bishop Tuff about 760,000 years ago.  Uplift and renewed eruptions then formed a resurgent dome in the center of the caldera.  The caldera is thermally active and has been the site of seismic swarms and other unrest for more than a decade. Photo by Larry Mastin, 1991 (U.S. Geological Survey).

The NE caldera wall of the 17 x 32 km Long Valley caldera, seen from Lookout Mountain on the west, forms a curved ridge that rises more than 1 km above the caldera floor. The caldera was formed following the eruption of the voluminous Bishop Tuff about 760,000 years ago. Uplift and renewed eruptions then formed a resurgent dome in the center of the caldera. The caldera is thermally active and has been the site of seismic swarms and other unrest for more than a decade.

Photo by Larry Mastin, 1991 (U.S. Geological Survey).


Long Valley