N1 – Solomon Memorial Grove

N1 – Solomon Memorial Grove Velocity Model

Key Info:

  • Site Class – D
  • AVS30 – 288.4 m/s
  • Peak H/V – 5.194 Hz

Survey Details:

  • # of Channels – 10
  • Min Wavelength – 5.4 m
  • Max Wavelength – 50m
  • Data Record Length – 1475 s

Survey Geometry:

  • Koichi 50m Triangle

Survey Notes:

This was the first NVSP passive seismic survey, a 10au 50 meter equilateral triangle array. It was a quiet morning, very little foot traffic or vehicular noise present. For a triangular array, and a first attempt at that, data came back surprisingly good!

Solomon Memorial Grove is named after Edward W. Solomon, mayor of Napa from 1988 to 1996. He was an educator and environmentalist. He served throughout the Napa Valley Unified School District in a variety of roles from teacher to principle to administrator. As mayor one of his major accomplishments was starting the Napa Flood Control Project, a major civil works project by the US Army Corp of Engineers. The flood control project was successful, and by following “living river” principles, the local river flora and fauna are now thriving.

The Solomon Memorial Grove is a short walk away from the Napa river, where the major objectives of the living river design can be seen. These include:

  • Reconnecting the river to its historic flood plain
  • Maintaining the natural slope and width of the river
  • Allowing the river to meander as much as possible
  • Retaining natural channel features like mud flats, shallows and sandbars
  • Supporting a continuous fish and riparian corridor along the river.

The most notable feature of the Napa River Project was what is known as the Oxbow Commons. This is a broad heavily vegetated area that connects the two parts of the Napa River oxbow loop together, with walking trails interspersed throughout. In the event of a food, this acts as an overflow , increasing the overall capacity of the water and mitigating food damage. Seismic data has been collected at the Oxbow Commons, N2 – Oxbow Commons, and 0.5 km south a passive-seismic survey was done across the river, achieving a depth of 125 meters. See N32 – Napa River.

Phase Velocity Dispersion Curve

N1 Phase Velocity Dispersion Curve

H/V Peak

Dispersion Curve

RMSE 13.83 m/s after five inversions.

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