DAS RFI POsted 17 Jun 2020.pdf

REQUEST FOR INFORMATION (RFI)

AIR FORCE RESEARCH LABORATORY (AFRL) SPACE VEHICLES (RV) DIRECTORATE

Nuclear Explosion Monitoring (NEM) Research Scientific Solutions

1. CONTRACTING OFFICE ADDRESS AND POINTS OF CONTACT (POC)

Department of the Air Force, Air Force Materiel Command (AFMC), Air Force Research Laboratory Detachment 8 – Space Vehicles Directorate, 3550 Aberdeen Ave, SE, Kirtland AFB, NM 87117-5776

CONTRACTING POINTS OF CONTACT (POC)

Ms. Anne C. Peel, Contracting Officer

AFRL/RVKB

Phone Number: 505-846-1075 Email: anne.peel@us.af.mil

TECHNICAL POINTS OF CONTACT

Dr. Raymond J. Willemann, Senior Research Geophysicist

AFRL/RVBN

Phone: 505-853-4333 Email: raymond.willemann@us.af.mil Dr. Frederick R. Schult, Senior Research Geophysicist

AFRL/RVBN

Phone: 505-846-6101 Email: frederick.schult@us.af.mil

The NAICS Code for this RFI is 541715.

2. DESCRIPTION OF INTEREST

The Government seeks to carry out a broad range of coordinated fundamental and advanced research that will accelerate development of decisive mission capabilities in geospace awareness through development of new algorithms to process data from seismic Distributed Acoustic Sensing (DAS) systems to detect, identify, and track rapidly evolving and emerging threats from underground nuclear tests. Seismic DAS is defined as use of a fiber optic cable as an array of thousands or tens of thousands of virtual strain or strain rate sensors to acquire seismic measurements at densities several orders of magnitude greater than systems currently used in nuclear explosion monitoring. Currently, many DAS systems rely on phase-sensitive Optical Time Domain Reflectometry (φ-OTDR) of Rayleigh Back Scattering (RBS), but the scope of this research extends to processing ultra-high density seismic measurements from any fiber-optic cable data acquisition technology that might be developed while this research is carried out. Priority will be given to applied and advanced research in the following categories that has the most promise for assessing and improving seismic event detection and characterization.

2.1 Applied Research

The applied research (i.e. Technical Readiness Level 2, https://www.army.mil/e2/c/downloads/404585.pdf) topics that the seismic DAS research for monitoring underground nuclear tests would address include the following categories.

2.1a. Characterizing Seismic DAS Signal and Noise.

Limited information is available about spatial coherence and other properties of noise within on-land DAS arrays and ultra-fine coherence of signals from seismic events outside of arrays. Information about noise is needed partly to understand what filtering, array processing, and other de-noising will best improve signal-to-noise atio. Good understanding of noise also may be useful for improving earth models, by analogy and extension of the ways in which cross-correlation of ambient noise between single-site seismic stations has mailto:anne.peel@us.af.mil mailto:raymond.willemann@us.af.mil mailto:frederick.schult@us.af.mil http://www.army.mil/e2/c/downloads/404585.pdf) been used to develop earth models. Good models of undersea noise are especially important, since some opportunities for improved monitoring arise from the possibility of deploying DAS arrays in international waters that are reasonably near monitoring targets and that now lack seismological monitoring sufficient for some missions.

2.1b. Evaluating Benefits of Alternative Seismic DAS Array Geometries.

To optimize performance against different objectives while meeting logistical constraints, conventional seismometer arrays have been crossed lines, L-shapes, concentric circles, Golay configurations, and other geometries. Different geometries may be preferred for DAS arrays for several reasons, including logistical constraints and noise characteristics. The response of DAS to oriented strain has unfamiliar implications for how array geometry influences directional sensitivity, which should be considered both for purposes of noise reduction and for improving sensitivity to signals from targets in selected areas. Investigation of signal sensitivity might be based partly numerical simulations of wave propagation producing synthetic strain or strain rate seismograms rather than conventional seismograms of displacement, velocity, or acceleration.

Regardless of the intended geometry of a DAS array, methods to more precisely locate the actual deployed location versus distance along the fiber-optic cable could improve the results from array processing.

2.1c. Developing Seismic DAS Array Processing.

The advantages expected from seismic DAS arise from the possibility of analyzing data from all of the gauge lengths as elements of a very dense array. Results from array processing should include improved S/N ratio and estimates of vector slowness even more so than with conventional arrays that are less dense, but there unexpected challenges, since some DAS studies have shown that the high density of virtual seismometers reveals delay time variability from earth structure under the DAS that was previously poorly known. DAS effectively oversamples the seismic wavelengths being measured, which may facilitate resolving source parameters that are inaccessible with data from a single conventional array. It may be possible to use array processing methods from other disciplines, but it would be important to evaluate their effectiveness for seismic monitoring and adaptation may be necessary partly because the response of DAS to seismic P, S, and surface waves are different. On the other hand, it is conceivable that the unprecedented density and element count of DAS may lead to use of innovative new array processing results.

2.1d. Developing Seismic DAS Detection Algorithms.

DAS detection capability has been demonstrated in a proof of concept manner by comparing DAS signals with events that are identified by conventional seismic networks. Unsurprisingly, stacking data along a segments of a DAS array improves S/N ratio of events signals in settings with high levels of both anthropogenic and natural environmental noise. DAS has been used to detect otherwise unknown events directly under an array or within a few kilometers of a vertical cable by visually inspecting visualizations of the data. For such dense arrays, it is possible that conventional short-term-average/long-term-average detectors may be significantly outperformed by continuous processing to discover coherent event signals standing out from incoherent noise. Time series of a cross-correlation statistics have been used in template-matching algorithms to vastly improve the earthquake detection thresholds compared with local networks of conventional seismometers.

2.1e. Developing Seismic DAS Networking Processing Algorithms.

The complete results from interferometric analysis for a 40-kilometer optical fiber comprises approximately 50 Gigabytes of data per hour. It is not practical to use the complete set of oversampled interferograms in association, but using only arrival time and vector slowness for association neglects potentially valuable information. Locations for otherwise undetected earthquakes have been computed in a few cases using classic single-station methods based on vector slowness from array analysis or by measuring an independent arrival time on each gauge length in a single DAS and computing a location from a very small aperture “network”.

But these locations have errors that are unacceptably large for operational monitoring of seismic events at regional distances. No paradigm for processing data from a DAS network has been formulated.

2.1f. Investigating the Event Characterization Capability of Seismic DAS.

The utility of seismic DAS for nuclear explosion monitoring will depend partly on the ability to compute source parameters consistent with those from conventional seismic data. For example, it already appears that coda envelope decay from DAS and conventional seismic sensors are very similar at all frequencies of interest.

Also, DAS can reliably measure phase and amplitude at frequencies relevant to computing seismic moment tensors, and solutions have been computed from an empirically calibrated DAS array by fitting observed strain to strain predicted from wave propagation modeling, but resolution of all moment tensor components from a small number of DAS arrays may require certain geometrical constraints. Developing methods to compute additional source parameter algorithms using data from a single DAS array is a worthwhile objective. The corner frequency of even very small earthquakes can be determined and it is plausible that data from a single DAS array also may resolve some features of source time functions, at least including total source duration, which can be useful in discrimination between single-shot explosions and ripple-fired mining explosions.

Speculatively, by analogy to use of frequency spectral ratios, wave number spectral ratios might be investigated as potential discrimination criteria. The oversampling of seismic wavelengths may facilitate use of machine learning techniques to characterize sources. Numerical simulations of wave propagation producing synthetic strain or strain rate seismograms may be useful in research on event characterization capability of seismic DAS.

2.1g. Seismic DAS Data Management.

The complete set of interferograms from a network of 40 DAS arrays would constitute nearly 50 Terabytes of data per day. A permanent archive might replace the interferograms with seismic observables, such as one-dimensional strain stored as 24-bit samples at 100 samples/second for each 10-meter gauge length. Even so, the network archive would grow at a rate of several Terabytes per day. While there may be strategies for managing such large data volumes, it would be helpful to develop more compact data products that retain all or most of the utility of data from a DAS array. Alternatively, DAS may motivate development of lossless data compression algorithms analogous to those that were common in telemetry of conventional seismic data decades ago.

2.1h. Improving Earth Models using Seismic DAS.

There may be applications in nuclear explosion monitoring of using DAS to study earth structure directly under conventional seismometers used for nuclear explosion monitoring. The broad frequency range measured by DAS – combined the very wide aperture that can be achieved affordably by renting use of fiber optic cables deployed for other purposes – has the potential to bridge between the resolution of very local studies earth structure and regional-scale models. Such “dark fiber” deployments are unlikely to include the broadside-sensitive cables that would be most advantageous, but innovative approaches to analyzing surface wave dispersion could provide useful information about earth structure despite the limitation of DAS to sensing strain in the cable direction. Even if the propagation paths of greatest interest cannot be directly characterized, simulation of propagation through models with stochastically-characterized fine scale structure might be improved by complementing the use of other measurements with improved extrapolation from regional structure to finer scales or by studying fine-scale structure in geological settings that are analogous to propagation paths of interest, addressing questions about the relative importance of topography and volumetric heterogeneity in scattering of teleseismic signals

2.1i. Investigating the Utility of Seismic DAS in Very Deep Boreholes.

Compared to conventional broadband seismometers, even helically wound fiber-optic cables can be deployed in much narrower boreholes and survive harsher environmental conditions. Thus, while conventional broadband seismometers are rarely deployed to depths greater than 100 meters, fiber-optic cables are deployed in deviated holes that go to depths of 4000 meters and sometimes then horizontally for thousands of meters and engineering R&D is underway to develop coatings for enhanced scattering optical fibers that facilitate DAS and are stable at temperatures typically found at depths of 5000 meters to 6000 meters. Vertical DAS deployments offer several potential benefits for nuclear explosion monitoring:

Less Surface Noise: The amplitude of noise induced locally at the surface continues to decrease with depth beyond 100 meters deep. Research might characterize further improvements in signal-to-noise ratios of local and regional phases at greater depths in different settings, such as geology and proximity to oceans, cities, and transportation routes.

Propagation Modes: Measuring the distribution seismic energy to 4000 m deep can improve inferences of how seismic energy is distributed among different propagation modes. Research might investigate using the modal distribution to constrain source depth, which is a criterion for discriminating between man-made explosions and naturally occurring earthquakes and useful to resolve the tradeoff of depth versus yield for source characterization.

2.2 Advanced Research

Beyond these several aspects of applied research, proof of concept (TRL 3) and laboratory environment validation (TRL 4) research would comprise linking various capabilities and demonstrating that together they generate more accurate, reliable, and timely high-fidelity monitoring products than are achieved today.

Advanced research might be based at least partly on funding from direct customers of AFRL or other interested agencies. Nevertheless, the coordinating role of the prime contractor would include activities to support advanced research, such as:

2.2a. Calibration of Existing Stations.

Advanced research might entail temporarily deploying seismic DAS arrays at existing arrays of conventional seismometers to improve calibration of vector slowness corrections and beam summation. Analysis of delay time variability and P-wave/S-wave velocity ratio within a DAS array can be used to map the faults and heterogeneity that gives rise to the need for empirical corrections and beam recipes. The density of virtual seismometers in a set of DAS arrays facilitates the use of tomographic methods based on local estimation of surface wave phase velocities and could map structure under existing arrays of conventional seismometers.

Advanced research also might entail temporarily deploying DAS arrays at existing single-site (three-component) seismic stations, since better information about structure at those stations could improve use polarization analysis, such as approximate estimates of back azimuth.

2.2b. Supplements to Existing Stations.

After a short-term seismic DAS experiment is completed, the interrogators are likely to be re-deployed for other R&D or, if leased, returned to the owner. Nevertheless, the fiber-optic cables in trenches and boreholes can be left in place and remain available for further use. When a potential benefit to monitoring is demonstrated, interrogators can be re-installed for further applied research, such as special analysis of events of concern. Permanent, trench-emplaced DAS might be prioritized at single-site (three-component) stations for the potential to improve network processing by significantly improving estimates of slowness and back azimuth, which can be used in applied research on network processing. Permanent, borehole-emplaced DAS might be prioritized at stations that are sufficiently close to regions of interest to facilitate applied research using reliable measurement of regional phases (Pg, Lg, Pn) to improve inference of depth from the distribution of energy among propagation modes.

2.2c. Deployment of Targeted Arrays.

New seismic DAS arrays may offer important improvements for event detection, location, identification, and characterization capabilities at selected sites or in selected broad areas. Applied research might entail developing recommendations for seismic DAS arrays at sites that are logistically daunting for conventional seismometers. If such arrays are deployed by the Government, then applied research might involve calibration of data processing.

2.3 Data Used in Research

Despite the multi-terabyte size of DAS datasets, some researchers have made their data available when they publish their analysis. Raw seismic DAS data are available primarily from research institutions and commercial organizations that have collected them. It will be the responsibility of the researchers to make arrangements directly with such organizations for access to data and data products and establish the utility of their selected data as surrogates for data used in operational nuclear explosion monitoring. If AFRL/RV participates in any independent seismic DAS data acquisition, it will be with an intention to make the data and processing resources available at AFRL/RC HPC facilities.

The researchers will be responsible decisions about use of the data, such as whether individual investigations that are part of the coordinated project make use of shared sets of data. The researchers will be responsible for quality control, such as ensuring that the metadata are accurate and that the data are representative of those typically used in operational nuclear explosion monitoring. If research could benefit from data acquisition using existing fiber-optic cable systems, such as the Dark Fiber Testbed of the Energy Sciences Network (ESNet) supported by the DOE Office of Science, then it would be the responsibility of the researchers to negotiate use of those systems.

2.4 Project Execution

2.4a. Coordination of Research Efforts

Potential offerors are invited to respond with research plans and rough order of magnitude cost estimates.

Responses should describe any plans to coordinate research and share intellectual resources among potential subcontractors, demonstrate the expertise in the fields involved, and identify likely areas of fruitful research.

While preparing responses, potential offerors may discuss ideas with NEM staff members and with other organizations with whom they might submit a joint response. The goals of soliciting RFI responses include:

2.4b. Request for Proposal

The Air Force could possibly utilize the STAR Advanced Research BAA solicitation # FA9453-19-S-0002 under topic area two for mission effects and capabilities based on the responses of this Request for Information.

2.4c. Award: Type, Ceiling, and Performance Period

The Air Force is considering an award as an Other Transaction (OT) for Research & Development. Other funding vehicles, such as a Procurement or Cooperative Agreement, will be considered and white papers should include indications of preferred vehicles. The objective is a vehicle for sustained efforts comprising a broad range of research and development that will transformatively improve nuclear explosion monitoring, other Air Force missions, and missions of customers of other AFRL/RV programs. The Air Force may award one or more vehicles that will not exceed ceiling of $20,000,000 (for all awards) and a performance period up to 5 years.

2.4d. Funding

After allowing for incremental costs on existing contracts and initial costs of anticipated new stand-alone awards, NEM expects to have at least $700,000 from its own funding during each year of the award. NEM would seek contributions from its Air Force customer and other agencies with relevant interests so that total core funding would be $1,000,000 annually. The prime contractor would be expected to use less than half of the core funding for coordinating activities described in the proposal.

During the first year, the Air Force expects the majority of funding to be used for fundamental research projects undertaken by a prime contractor and subcontractors and described in a proposal. During subsequent years, the Air Force expects the majority of core funding to be used for research projects that advance the strategic plan, using procedures that ensure each project is carried out by a participating organization with appropriate expertise. Contingent on available funding, the Air Force may provide additional funding during certain years, for research projects selected using the same procedures and that accelerate progress towards the objectives of the strategic plan.

2.4e. Special Projects

Additional AFRL/RV funding during some years might be for special research projects by subsets of the prime contractor and the subcontractors. AFRL/RV would provide a statement of objectives to the prime contractor and some or all of the subcontractors about interest in a special research project. Through processes among the organizations, some set of them would participate in preparing a proposal that the prime contractor would submit to AFRL/RV. AFRL/RV would perform a technical evaluation of the proposal and, if it is acceptable, the funding would be provided to the prime contractor, which would distribute it among the subcontractors in accordance with the negotiated terms of the award.

2.4f. Other Funding

To pursue further research projects related to the objectives of the Air Force or to enhance the coordinating activities related to the objectives of the Air Force, and in consultation with AFRL/RV, the prime contractor could seek and accept further funding from other Federal government agencies, from U.S. state government agencies, from U.S.-based and internationally recognized corporations and foundations, or from intergovernmental agencies.

2.4g. Role of a Prime Contractor

A potential lead offeror might submit an RFI response for a coordinating role leveraging prior arrangements with several potential subcontractors. The potential lead offeror might intend to submit quarterly, annual, and final reports on coordinated research, to include progress on and results from research projects by subcontractors.

An RFI response might describe further coordinating activities intended to foster wide expertise and a collaborative approach to delivering transformative capabilities in nuclear explosion monitoring. The coordinating activities might include some or all of these examples:

• Develop a strategic plan to identify essential avenues of research, carry out research into various avenues, and integrate research products into an effective system.

• Hold meetings of researchers from subcontractors and from selected other organizations to review research accomplishments and, as necessary, update or revise the strategic plan.

• Establish a mechanism to share intellectual resources, such as vetted datasets. Some of the resources might be restricted to researchers affiliated with institutions that are subcontractors, while other resources might be openly available.

• Organize on-line activities, such as webinars, to develop shared expertise.

• Convene short courses or training institutes for early-career researchers affiliated subcontractors and from selected other organizations to develop a collaborative community of next-generation researchers.

2.4h. Subcontractors

Initially, subcontractors would be organizations named in a proposal. The mix of subcontractors could change to meet emerging research needs, as the discretion of the prime contractor in consultation with AFRL/RV.

3. REQUIRED ADDITIONAL INFORMATION TO BE SUBMITTED

a. Company Name and Mailing Address

b. CAGE Code and DUNS Number

c. Point(s) of Contact

d. POC Telephone Number and e-mail Address

e. Business Size Status (i.e. 8(a), HUBZone, woman-owned, Service Disabled Veteran-

Owned, Small business, Large Business, Historically Black College/University) under NAICS 541715; the associated small business size standard is 1,000 employees

f. Relevant experience in the past five years in the technical areas of interest

g. Availability of an adequate number of qualified personnel to support the effort

h. If an Other Transaction is desired a rough contract is requested with terms and conditions

Note: If a solicitation is released, it will be synopsized on the System for Award Management Beta (SAM Beta) website (https://beta.sam.gov/). It is the responsibility of potential offerors to monitor the website for additional information pertaining to this notice or a requirement that may relate to this notice.

4. FORMAT & SUBMISSION

Interested businesses are requested to respond no later than 30 July 2020; 3:00 PM MDT. Please provide sufficient detail to indicate technical approach, procedures for coordinated activities, contract type preference, rough order of magnitude (ROM), previous experience, and supporting information that directly relates to the areas of interest identified in this request for information. Submittals should be submitted in accordance with the white paper instructions and white paper template format located in the STAR Advanced Research BAA solicitation # FA9453-19-S-0002 on https://beta.sam.gov/.

Submittals should shall be submitted electornically via SAFE at https://safe.apps.mil/. When uploading your documents the Government desires a searchable .pdf or Microsoft Word compatible format. Please do not mail packages.

Responses must be unclassified and any proprietary information provided must be portion marked accordingly. To protect such data, each line or paragraph on the pages containing such data must be specifically identified and marked with a legend similar to the following:

“The following contains proprietary information that (name of responder) requests not be released to persons outside of the Government, except for the purposes of review.”

Submitted responses should be provided on standard letter size 8-1/2 by 11 inch paper, limited to a maximum of fifteen (15), single-sided, single-spaced pages. The font for text should be Times New Roman 12-point or larger. The Responder may use oversized pages (including “foldouts”) where appropriate to contain graphic presentations. Oversized pages do not count as extra pages within the page limitations. Existing commercial documentation and product literature can also be submitted in addition to the 15 pages above and is not subject to a page limitation.

All information received shall be safeguarded from unauthorized disclosure. Responses must be unclassified and any proprietary information provided must be marked accordingly. This is not a Request for Proposal (RFP) and is not to be construed as a commitment by the Government to issue a solicitation or ultimately award a contract. Any costs incurred as a result of this request for information shall be borne by the respondent and will not be charged to the Government for reimbursement. If your interest is only in subcontracting possibilities, please clearly indicate this on the cover page. Foreign firms are advised that they will NOT be allowed to participate under ITAR rules; please contact the Contracting Officer for conditions and restrictions.

All submissions become Government property and will not be returned.

5. REQUESTS FOR CLARIFICATION

A Responder may request clarification in writing to the Contracting Office for any requirement that is unclear by sending an e-mail to the Contract Officer identified above.

Any requests for clarification must be received no later than 15 July 2020; 3:00 PM MDT. Note: clarifications may be posted to benefit all interested Responders; do not include proprietary information in the clarification request. Interested parties are encouraged to periodically check the website during the response period for clarifications.

6. DISCLAIMER

This is a Request for Information (RFI) ONLY as defined in FAR 15.201(e) to obtain information about capabilities and market information related to the technology of interest for planning purposes. This RFI is NOT a request for competitive proposals; therefore, responses to this notice are not considered offers and cannot be accepted by the Government to form a binding contract. Companies that respond will not be paid for the information submitted, nor is the Government required to provide feedback to RFI responders.

https://beta.sam.gov/ https://beta.sam.gov/ https://safe.apps.mil/