16.6 MB pdf - IRIS

Solid-Rock Corehole Sensor Placement
Overview
TA, Bob Busby, Allan Sauter, April 2012 - ongoing.
Using a relatively light-weight core drill, we have cored several 4’ holes into solid rock
with a 6 or 8” diameter, large enough to deploy Guralp 3T’s, Nanometrics PH120, and
the new STS-4B’s. We have developed methods of orienting, packing, insulating, and
bear-proofing the sensor.
Objectives
To develop seismically acceptable, lighterweight
sensor placement methods that will
work in AK
C
ff
50 m
augered/drilled
holes (5-110 m depth)
Scope
This is a new project for 2012
Project investment:
2weeks engineering/procurement 4-6
solid rock
cored holes
(~1 m depth)
Albuquerque Seismological Laboratory (USGS)
-50
-100
-150
mini-vault
(1 m depth)
direct burial
(1 m depth)
Dotson Ranch Test Site (IRIS/NMT-PIC)
Frequency (Hz)
10 1 0.1 0.01 10 1 0.1 0.01
-200
ANMO BHN (1 month) TASM BHN (1 month)
Figure IS-2. Instrumentation Services is coordinating a variety of sensor emplacement
tests - summarized in this notional graphic. Test plans and project status
are briefed to the entire IS Team as part of the IS Engineering Process (upper left).
Testbeds are created, ranging from soft soil installations representative of typical
portable installations (upper right), to shallow solid rock and intermediate depth
boreholes co-located with a USGS-operated GSN site (lower left). Data are analyzed
using Power Spectral Density techniques and other tools (lower right - from
IRIS DMC automated QC processes) to measure results. The goal is to identify cost
efficient emplacement strategies that yield optimum performance for different
field conditions, using documented techniques that can be scaled to experiment
goals and budgets.
process facilitates a comprehensive sharing of information
and often establishes connections and cross-project synergies
that were not previously exploited.
Finally, best practices in management means taking a team
approach to Instrumentation Services. IS managers meet
regularly as a team to review program status, identify issues,
and coordinate activities. Subaward and procurement plans
are reviewed and compared to identify potential synergies or
savings. Routine policies and procedures that impact day-today
efficiency are reviewed and refined. Plans and interactions
with other programs or directorates within IRIS are identified
and often consolidated. Communication with IRIS governance
structures is also enhanced. For example, the committees
that advise IS programs have held joint and/or overlapping
meetings and IS managers coordinate materials so that
committees are presented with a common level of detail. The
Board receives integrated briefings and can now take a more
pan-IRIS approach to instrumentation—by providing guidance
and feedback on behalf of the community that is implemented
consistently and appropriately across all IS programs.
Looking ahead, several new activities provide significant
benefits across all of IS and will be managed and coordinated
as pan-IS activities rather than executed within any
one IS program. These activities, described in Section 3.1.8
(IS Coordinated Activities), include two key technology
demonstration efforts, a seed effort to grow a future international
program, and structured promulgation of instrumentation
best practices. These activities form a suite of investments
in the future of IRIS instrumentation facilities and
services. The New Technology effort is particularly important
as it will leverage emerging technology to create instrument
Power (Db)
systems that are smaller, lighter, use less power, and cost less.
This effort is of interest Consortium-wide, and IS has motivated
and facilitated discussions that have already engaged a
large part of the community (as discussed further below).
The entire set of Instrumentation Services activities are
discussed in the following subsections, including the new IS
Coordinated Activities.
Proposed Activities
3.1.1. Management
All of IRIS’ instrumentation-related senior management are
pulled together in an IS management team to ensure tight
coordination. Under the leadership of the IS Director, this
team oversees all of IRIS’ instrumentation programs, with
each of the senior staff leading one or more major efforts. Each
manager oversees staff, budgets, subawards, and procurement.
As a team, this group engages in coordinated planning
and budget preparation—among themselves, pan-IRIS
and with the Coordination Committee and the Board. In
cases where subawards serve multiple projects the work statements
are coordinated and consolidated (e.g., the New Mexico
Tech subaward activities are coordinated across Portable
Seismology, TA, and Polar Support Services). Procurements
with equipment suppliers, both large and small, are coordinated
and, where appropriate, bundled for better pricing and/
or efficiency (e.g., sensors, station vaults, cellular modems).
The Director of IS represents this IS management team on the
IRIS Senior Management Team. This facilitates information
flow and coordination, vertically and laterally, and ensures
efficient use of the group’s time.
3.1.2 Governance
The community is involved in IS activities at a deep and
fundamental level. The current governance structure includes
standing committees for GSN and PASSCAL, a USArray
Advisory Committee, a Polar Network Sciences Committee,
and the Instrumentation Committee. Working groups have
been created to provide more detailed technical guidance
to the TA (the Transportable Array Working Group) and to
MT (the Electromagnetic Working Group). The individual
programmatic governance structures are described in greater
detail below. As discussed earlier in the proposal, the IRIS
Board of Directors is currently looking at the evolution of the
governance structure and considering a more closely aligned
overlay between governance and management. Given the
tight communication and feedback already in place, IS can
readily accommodate the evolution of the governance structure
as needed/desired.
I-26 VOLUME 1 | Section I | 3.1. Instrumentation Services