The 18 May 1980 eruption of Mount St. Helens, emplaced between 3-3.5 billion cubic yards (bcy) of poorly sorted material ranging from silt to boulders, extending from river mile (RM) 25 to RM 38 in the upper North Fork Toutle River drainage. Sediment yields from the debris avalanche were calculated...
The effects of burial by tephra (volcanic aerial ejecta) on
forest understory plants were examined northeast of Mount St. Helens,
Washington, in the area where the 18 May 1980 eruption deposited
tephra but did not destroy canopy trees. At six sites along a tephra
depth gradient from 2-15 cm, understory...
Field and laboratory studies were conducted on volcanic ash from Yakima, Moses Lake, Spokane, Washington, and Moscow, Idaho, three weeks after the May 18, 1980, eruption of Mt. St. Helens in southwestern Washington. These studies examined 1) the chemical, physical, and water retentivity properties of the ash, 2) the effect...
Comprehension of eruptive histories is critical in understanding the evolution of magmatic systems at arc volcanoes and may supply evidence to the petrogenesis of intermediate and evolved magmas. Within the 300 ka eruptive history of Mount St. Helens, Washington, the Kalama Eruptive Period, 1479- ~1750 CE was bracketed by interludes...
Riparian vegetation patterns within the blast,
downstream of blast, and airfall tephra zones of Mount
St. Helens are related to initial and secondary volcanic
disturbance, post-eruption fluvial landforms, channel
geometry, and streamflow characteristics. Vegetation
patterns were determined from species presence observed on
transects across landforms developed along the streams.
Distinct...