Golden Trout Creek Volcano - John Seach


California, USA

36.358 N, 118.32 W
summit elevation 2886 m
Volcanic field

The volcano consists of a group of cinder cones and lava flows in the Toowa Valley.

Toowa Valley is broad and open, about 8600 feet high, with cones 400-600 feet above the valley floor. Four volcanic centres are identified at Golden Trout Creek Volcano.

Tunnel Volcanic Center
Three eruption phases occurred at the volcanic centre. A small cone of cinders about 15 m high is constructed on a low ridge of quartz. Pumiceous, olivine basalt, flowed over the low cinder cone rim. Olivine basalt erupted from the central vent adjacent to the quartz ridge and extended north and south, forming layers 3 m thick.

South Fork Volcanic Center
Three eruption phases occurred at the centre. Vesicular basalt flows, 3 m thick, extend west and southwest base of South Fork cone, west along Golden Trout Creek and disappear under overlapping lavas from Groundhog Center. An eruption of cinders produced the bulk of South Fork Cone. The cone summit is 200 m above the present stream. A central plug of basaltic scoria was erupted on the south and west rim of the cone. South Fork cone is breached on the north by a distinct break.

Groundhog Volcanic Center
Five eruptive phases have been identified at the volcanic centre.

1) In the first phase highly fluid basaltic magma, erupted from centers near the present west base of Groundhog cone, flowed west, along the north side of the valley of Golden Trout Creek, and displaced the stream. A gorge 270 m deep at the junction with Kern Canyon was almost completely filled by flows from this eruption.

2) The second phase produced eruptions from Groundhog Center from fissures on the south side of Toowa Valley.

3) The third eruption from Groundhog center produced black basaltic aa lava covering nearly 3 square miles of Toowa Valley. The eruption originated from a series of well defined vents circularly arranged about the Groundhog cinder cone.

4) The fourth phase of volcanic activity produced Groundhog cone. The cone rises 270 m above the volcanic field. The cone contains scoria, ash, cinders, and bombs of varying sizes. Spindle bombs and scoria blocks 2 m in diameter were produced in the eruption.

5) The final phase of Groundhog Center produced a single flow of massive olivine
basalt, originating within the crater and extending north through the breach, flowing
about 25 m before congealing.

Little Whitney Volcanic Center
Five eruptive phases have been identified at the volcanic centre.

1) The first phase erupted a large basaltic lava flow about 7 m thick, extending from fissures northeast of the present cinder cone. This flow extended 100 m from the vent, and displaced a small stream to the east.

2) During the second phase a large basalt flow was also erupted.

3) The third phase produced a small cinder cone built on a bedrock ridge, extending southeast across the head of Little Whitney Meadow. The cone is composed of cinders of basaltic scoria less than 3 cm in diameter.

4) A smaller inner cone of pyroclastic material was built during the fourth phase.

5) The fifth phase consisted of extrusion of a small basaltic flow from a breach in the south wall of the older outer cone, and produced a flow about 50 m long.

2009 Earthquakes
On 3rd October 2009 a series of earthquakes up to magnitude 5.2 occurred on the eastern edge of Golden Trout Creek Volcano.

Golden Trout Creek Volcano Eruptions

5550 BC ± 1000