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The San Francisco Bay Region is bounded by distinctive mountains
including the Santa Cruz Mountain Range and the Diablo Range.
These mountains are constantly shaped by erosion and landslide
activity. Homes and structures built in these hillside environments
may be susceptible to landsliding. Landslides cause $1-2 billion
in damage and more than 25 fatalities on average each year within
the United States.
Several different types of landslides and landslide hazards may
impact projects in hillside terrain such as deep-seated bedrock
landslides, shallow soil slumps, or rapid-moving debris flows.
Landslides may be active, dormant, or old and relatively stable.
The relative age of landslides may be inferred by the morphology
or shape of landslide features. Landslides can be triggered, or
old landslides may be reactivated, in response to grading activities,
to prolonged rainfall, or to seismic shaking on nearby active
faults.
Counties and Cities may require Landslide Investigations to determine
if landslides pose a hazard to proposed developments in hillside
environments. Recently-adopted State regulations may also require
landslide investigations.
I can design a Landslide Investigation for your project to satisfy
requirements of regulatory agencies. The investigation may include
excavation of test pits or borings to confirm the presence or
absence of landsliding. Large diameter borings, designed to safely
lower a geologist into a borehole to log and sample subsurface
materials, may also be utilized.
The scope of the Landslide Investigation will be designed to meet
the State, County, and City requirements for your project and
may include:
- review of geologic maps, literature, and air photos,
- site reconnaissance and mapping,
- consultation with the Reviewing Geologist,
- consultation with the project Engineers and Architects,
- excavation and logging of test pits and borings,
- drafting and report preparation.
The Landslide Investigation will produce detailed logs, a site
geologic map, and cross-sections which define the limits and geometries
of identified landslides and assess the risk to proposed improvements.
Appropriate setbacks or mitigations and landslide repairs will
be recommended where feasible. Alternatively, slope stability
analysis may be performed to assess the potential for reactivation
of old and dormant landslides. |
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