Jon J. Major
U.S. Geological Survey, Cascades Volcano Observatory
1300 SE Cardinal Court, Suite 100
Vancouver, WA 98683
phone: (360) 993-8927
fax: (360) 993-8980
email: jjmajor@usgs.gov
- Project Description:
- Volcanogenic processes at explosive
volcanoes can profoundly disrupt watershed
hydrology, geomorphology, and sediment yield in
multiple ways. Hillslopes disturbed by
volcanogenic processes can be mantled by
sediment transported by pyroclastic
processes or by tephra fall, and vegetation
can be defoliated, razed, buried, or
completely removed. It is now well documented
that water discharges and sediment yields
can be radically altered following eruptions,
yet there are few studies that attempt to link
those changes with changes in the fundamental
hydrologic processes in watersheds.
Presently lacking are detailed studies
identifying dominant hydrological processes and
geomorphic responses following volcanic
eruptions as well as studies
defining long-term geomo
rphic and hydrologic recovery of watersheds
disturbed by volcanic processes.
The project focuses broadly on identifying
the dominant hydrological mechanisms that
are disturbed by volcanic eruptions,
their specific influence on hydrological runoff,
and on long-term recovery of volcanically
disturbed watersheds. In-situ instrumentation,
field and laboratory experiments,
analyses of aerial photographs, repeated
channel surveys, and continuous
measurements of water and sediment
fluxes are used to determine relations
between precipitation, surface- and
subsurface-water runoff, sediment yields,
streamflow discharges, and channel evolution.
Results are used to characterize and model the
evolution of geomorphic and hydrologic recovery
of watersheds following volcanic eruptions;
to promote a greater understanding of
watershed disturbance and recovery among
technical professionals, public officials,
and the general public; and to enhance the
U.S. Forest Service Mount St. Helens National
Volcanic Monument interpretive program.
- Publications and Reports
- Other Menus of Interest
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