The USGS Cascades Volcano Observatory (CVO) constructed the Sediment Lab (SedLab) during the 1980s as an aid to study the sediment released during eruptions of Mount St. Helens. Now, decades after those eruptions, sediment within the rivers leading from the volcano remains unsettled and continues to increase flood potential and prohibit fish return to some river environments.
Today, the CVO SedLab serves the sediment analysis needs of USGS scientists and other partners in the Pacific Northwest, Hawai‘i, Alaska, and Guam. Staff conduct concentration and particle size distribution analyses on a wide variety of lahar and tephra samples. The facilities are capable of handling samples from large bedload gravels to small amounts of suspended sediment.
- Suspended sediment concentration by evaporation
- Suspended sediment concentration by filtration
- Sand break
- Grain-size analysis by wet sieving (full phi or half phi)
- Grain-size analysis by dry sieving (full phi or half phi)
- Fine size analysis by SediGraph (full phi or half phi)
- Loss on ignition
- Dissolved solids test
- Sediment specific gravity/mineral density
- Bulk density
- Fine particle size by imaging analysis (experimental)
- Scanning electron microscopy
Active research produces new techniques and improved instrumentation
The CVO SedLab works closely with scientist in providing authentic and reliable data to support their research. In addition to our analytical facilities, SedLab operates active research and development projects in particle size instrumentation design. Our focus is on using optical imaging to measure the particle size distribution and particle shape of very light suspended sediment samples.
Services are available to other government entities, universities, and Indian Tribes.