Ascente Faults

The bottom line … The first Ascente Final Map shows residential construction on a fault identified by the Nevada Bureau of Mines. It is commonly called the Galena Creek Fault. It is drawn as a dashed line.

There’s a lot more to the story, but the county should be concerned that they have accepted a misleading Geotech report for this project.

Principals:

  • NNV1 Partners: developer
  • Toll Brothers: builder
  • Lumos & Associates: Civil engineering firm
  • Gasch Geophysical Services: Soils engineering
  • Fred Saunders: Consulting geologist

Roles

  • A Lumos civil engineer selected the trench locations. Lumos dug the trenches. These trenches were poorly located, poorly dug, and poorly documented.
  • Gasch used seismic testing to determine the structure of the underground rock formations for the purposes of grading. The testing is conducted with a line of vibration sensors and an impact device. It is called a “refraction seismic line” (RS). The results may also detect an earthquake fault. The RS line locations were selected by Lumos.
  • Fred Saunders reviewed the work performed by Gasch and Lumos

The graphic below shows the Ascente Tentative Map superimposed on the fault map using Photoshop Elements. The maps used had consistent North-South orientation. The maps were superimposed using the end of Fawn Lane and the end of Shawna Lane as reference points. See the attached file for the reference materials.

Notes from the graphic

Note-1: Gasch found a fault indication on RS-4. “ … corresponds well to the fault trace previously mapped to this area.” Saunders said “it could be reinterpreted”, but concluded that Lumos should take a core sample to find out. No core sample was taken.

Note-2: Trench 3 is very close to the GC fault. Saunders reported that no fault was found, but there appeared to be fault debris in the trench and in the soil that was excavated.

Note-3: Trench-4 showed evidence of a fault. It was dismissed by Saunders as “too old”, but this is implausible.

The “NEW FAULTS” are ones discovered by the Lumos trenching.

Conclusions

  • The first final map of 5 home sites appears to be situated on top of a major fault identified by the Nevada Bureau of Mines.
  • The Geotech report submitted by Lumos is inadequate in every way. The trenches were not located by a geologist who would know what to look for. The trenches were not dug to industry standards and were not documented (“logged”) to professional standards.
  • Lumos did not follow up with additional core samples or trenches at locations where there was evidence of the Galena Creek fault.
  • The “known fault” at the north end of the property may extend into the property. No trench was dug nor core sample taken to locate the end of this fault.
  • The northern end of the “new fault” in Donner Village was not found. It may extend further into the development.

The deficiencies in the Geotech survey were reported in to the County Engineer and Planning Manager in December of 2017. The local geologists that authored this letter received no reply.

The developer has an incentive to minimize the faults found on the property so as to be able to build the maximum number of homes. The engineering company is paid by the developer. The geologist is paid by the engineering company. There is good reason to be skeptical of such a report.

REFERENCE MATERIALS

Gasch Report

Saunders Report

Lumos Summary

Note: the complete Geotech report includes many pages of soil characteristics, foundation design, and other details not pertinent to the fault issues.

5 thoughts on “Ascente Faults

  1. Thanks Steve!
    It’s so important to remember that the job of Ascente and their “geotechnical” consultants is to prove WHERE the faults are, as shown on the STATE Geologic map. Just plonking down trenches and resistivity lines in the general are (a bit to the left, right, east or west) of the inferred map location, and not finding the faults, does NOT prove that they are NOT there! We have previously argued to the County that the 2017 field work was egregiously lacking in robust field investigation necessary to prove the inferred State Geologist’s mapping. Specifically, we saw that the Trench 3 showed evidence of faulting in the trench cuttings and along the walls of the trench itself, as this trench just happened to remain open overnight and thus accessible. We could not enter the trench because it was not shored up as required by health and safety regulations, and proper techncial protocol. If we couldn’t enter the trench, the field geologist couldn’t either. Therefore, his “mapping” was haphazard, and based on the same cursory examination as ours. We saw evidence of a fault, and he didn’t.

    Who was paying him? Did it behoove him to ignore the slickensides and other evidence presented in the cuttings? One more trench, properly located and accurately logged and mapped according to standard geotechnical practice (several are available on the internet including the USGS and ASTM Standards) would have taken care of the issue. But then it also likely would have stricken several home sites off the Ascente Tentative Map, thus less money made.

    Four years later, the unprofessional nature of this “investigation” and lack of follow-through by the County leaves me angry. These are Holocene faults! They have moved in the last 10,000 years and are likely to move again, during the next “Big One” in Washoe Valley.

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  2. Steve:   The WCSD produced the same type of faulty (no pun intended) report to back the location of the Marce Herz Middle School on Thomas Creek Lane.  Money talks.  When the quake hits, these people will probably all be retired and free from any responsibility.   Jim Verner

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  3. Steve: This whole development has been fraudulent from the start.  I attended the planning commission meetings years ago.  Opposition from the area residents was nearly unanimous.  At the meetings I pointed out that part of the development was planned around the foot of a volcano that probably erupted less than a million years ago.  The response from Lumoswas that they didn’t know that.  The Planning Commission and the County Commission both approved the project.  I think Commissioner Lucey had the most influence in this.  I have seen other instances of corruption around the country.  In one instance, the county commission approved a housing development above a shallow underground mine.   several houses fell into the mine, but no one has been brought to account for the losses. I’d be glad to talk with you further. Carl M. Welch, R.G.(775) 530-4349

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