the Sand and Mud
Online videos related to San Francisco Bay sand and mud, produced by USGS and partners.
At the glacial maximum, the central Californian coastline near lay near the edge of the continental shelf, outboard of the Farallon Islands ridge. San Francisco bay and its related waterways were dry-land river valleys. As sea level rose during the glacial meltdown, the coast gradually moved inland, across the shelf and into the bay. The sea extended well into California's central valley but was then filled in to form the Sacramento/San Joaquin delta and estuary.
USGS scientists explore how sediment moves across San Francisco Bay tidal flats. The research team deploys a suite of large instrumented tripods to record sediment movements over a six-week period in early 2011. Answers from this work will help determine whether deposition of sediment at high tide is occurring quickly enough to preserve marshes in the face of sea-level rise.
Virtual fly-through of San Francisco Bay revealing the seafloor as if the water was drained from the Bay. The movie flies through the south and central Bay, pausing over prominent seafloor features including, large sand waves, rock pinnacles, current scour pits, as well as many human impacts on the seafloor.
Virtual fly-through over the seafloor of Central California near San Francisco as if the water was drained from the ocean. The seafloor is colored for depth with reds and oranges representing shallower regions and dark blues and purples representing deeper regions.
The role of science in restoring south San Francisco Bay salt ponds to wetland habitat.
"Delta Science" is an excerpt from the USGS produced television program "Delta Revival: Restoring a California Ecosystem". The segment shows how USGS scientists are working to guide the restoration of the Sacramento-San Joaquin Delta through studies of ecosystem responses to toxic contaminants, invasive species and water diversions.
Animated GIF of hydraulic mining debris deposition and subsequent erosion in north San Francisco Bay. Details here.
Animated GIF of hydraulic mining debris deposition and subsequent erosion in San Pablo Bay. Details here.
USGS research seminar.
As sediments accumulate over time, they create records geologists use to understand Earth history and to predict future processes and trends. Vibracoring is one of the tools used in shallow coastal areas where sediments consist of soft sand and mud. This video podcast describes how cores are collected in shallow water from the deck of a research vessel using vibracoring.
Temporal mapping and spatial analysis of land transformation due to urban development. Details here.
Development can have negative effects on streams in urban and suburban areas. As a watershed becomes covered with pavement, sidewalks, and other types of urban land cover, stream organisms are confronted with an increased volume of storm water runoff, increased exposure to fertilizers and pesticides, and dramatic changes in physical living spaces within the stream itself.
USGS research seminar.
This time-lapse video shows the dramatic natural tidal cycles of a salt marsh in San Francisco Bay - daily rhythms to which animals take refuge in high ground, and the marsh receives sediment and nutrients from the estuary.
The animations depict projected sea-level rise at each marsh. Dark blue represents mean high water level, light blue is mean sea level. The marsh platform is accreting a constant 1.9 millimeters per year, sea level rises 0.4 meters by 2050 and 1.0 meter by 2100.
A catastrophic 1982 rainstorm triggered 18,000 landslides in the Bay Area, claimed 25 lives and caused $66 million in property damage. The combination of steep slopes, weak rocks, and intense winter storms make Bay Area uplands an ideal setting for landslides. Landslides include both swift, potentially deadly debris flows and slower, but destructive deep-seated slides. Hear the devastating stories of Bay Area residents affected by landslides and learn to recognize the danger signs.
This video about tsunami preparedness along the coast of Central California distinguishes between a local tsunami and a distant event and focuses on the specific needs of this region. It offers guidelines for correct tsunami response and community preparedness from local emergency managers, first-responders, and leading experts on tsunami hazards and warnings who have been working on ways of making the tsunami affected regions safer for the people and communities on a long-term basis.
This video presents information on historical and recent earthquake activity in the Bay Area of California. Experts discuss scientific and engineering issues, as well as personal safety and community well-being. The 7 Steps to Safety are neatly outlined, showing families how to be prepared before, during, and after an earthquake.
Shock Waves is an Emmy Award nominated USGS television program. It traces the century of scientific and engineering progress since the great quake. Historical recreations, hundred-year-old film footage, and stunning still photographs convey the extent of the destruction and the human and scientific response to the catastrophe. The program features 3D animations, cutting edge research and expert interviews with some of the world's premiere seismologists and engineers.