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Current, Emerging, and Frontier Capabilities of Seismological and Geodetic Facilities

Lucy Flesch (Purdue University), co-chair of the 2015 community workshop organizing committee, and Rick Aster (Colorado State University), co-editor of the 2015 community workshop report writing committee, were invited to provide background about that workshop. This was to familiarize workshop participants with the emerging and frontier seismological and geodetic facility capabilities that were defined at the 2015 workshop, and to summarize relevant report sections. Their presentations were followed by a moderated question and answer period between speakers and audience.

DESCRIPTION OF THE 2015 COMMUNITY WORKSHOP

Lucy Flesch, Purdue University

Lucy Flesch was co-leader of a 2015 workshop organizing committee charged by the National Science Foundation (NSF) with gathering community input to identify the most important geophysical scientific questions, research opportunities, and broader impacts to be pursued in 2018 and beyond. She described how the charge to the organizing committee also included gathering input on the seismic, geodetic, and magnetotelluric facility capabilities required to support research and associated education, outreach, training, and workforce development. Two types of seismological and geodetic capabilities were to be defined: those necessary for geoscience research to occur as practiced today (foundational capabilities), and new capabilities required to allow for rapid progress in addressing scientific grand challenges (frontier capabilities).

The organization of the workshop was informed by community input obtained through 4 webinars and 91 white papers solicited prior to the workshop, according to Flesch. There were 120 workshop attendees. The workshop was divided into four science-based plenary sessions with breakout discussions as part of each plenary: (a) Earth structure, rheology, and geodynamics; (b) time-variant behavior of faults and magmatic systems; (c) evolving landscapes and global environmental change; and (d) links to industry

and discovery-mode science from new technologies. She said that participants were asked to define the scientific questions to be pursued through geoscience research, as well as the foundational and frontier geodetic and seismic facility capabilities required to advance geoscience research and education beyond 2018. A final plenary discussion synthesized workshop findings.

According to Flesch, development of community seismological and geodetic facility Centers of Excellence that are available to the scientific and broader community has been key to the scientific and cultural transformation of geophysical disciplines over the past several decades. Flesch concluded with two key points derived from the workshop: (1) future facilities need to be dynamic, responsive, integrative, and agile; and (2) facilities are more than their physical infrastructure; they are centers that catalyze integrative education, diversity and inclusion, and broader public outreach.

DESCRIPTION OF CURRENT, EMERGENT, AND FRONTIER CAPABILITIES

Rick Aster, Colorado State University

Rick Aster described historic advances in geophysics and related disciplines catalyzed by NSF-supported facility Centers of Excellence. Those centers are focal points for community collaboration and professional and leadership growth for researchers at all career levels. They are sources for experiment technology support and of professionally curated and openly available data and metadata. Aster also described the importance of facilities remaining responsive to scientific and community needs. Continued and expanded intra- and interagency leveraging is necessary, he explained, for continued success of future seismological and geodetic facilities.

According to Aster, access to the facilities is democratized so that principal investigators and students from diverse institutions may take advantage of research opportunities, training, and professional staff. The facilities are optimally used and directed as a result of the strong user community support and engagement.

He then described how the 2015 workshop report further split capabilities into three categories:

• Existing foundational capabilities: those that are fundamental to current and near-term science directions, including the continuation of currently supported NSF projects;
• Emergent foundational capabilities: those incorporating current technologies to drive significant progress on major high-priority science challenges for 2018 to 2023; and
• Frontier capabilities: presently nascent capabilities considered important for trans-formative science.

Table 2.1 summarizes those capabilities in each category as defined in the 2015 workshop report and described by Aster. Aster then summarized capabilities envisioned for the future (noting that progress toward some of these have been made since 2015). Those capabilities include:

• Near real-time daily maps of deformation derived from Global Navigation Satellite System (GNSS) instrumentation and orbiting radar satellites;
• Globally distributed seafloor and surface-drifting geophysical instrumentation;
• Arrays of distributed acoustic sensing fiber optic cables providing continuous high sample rate surface strain;
• Customizable drones that can host or deploy a range of instrumentation;
• Larger instrumentation pools to routinely deploy in diverse environments and across a range of scales to record the full frequency-wavenumber spectrum and range of transient and ambient seismic wavefields;
• Global telemetry providing high-rate and low-latency sampling from remote seismic, geodetic, and other multidisciplinary instruments; and
• Routine access to high performance computing and associated capabilities for data reduction and model inference on an unprecedented scale.

Table 2.1 Capabilities of Seismological and Geodetic Centers of Excellence Defined in 2015^a

^a Parentheticals indicate the facility/ies where specific capabilities are housed.

^b Significant progress made on some of these capabilities since the 2015 workshop.

NOTE: GAGE = Geodetic Facility for the Advancement of Geoscience; InSAR = Interferometric Synthetic Aperture Radar; NISAR = National Aeronautics and Space Administration—Indian Space Research Organization Synthetic Aperture Radar Mission; SAGE = Seismological Facility for the Advancement of Geoscience; WinSAR = Western North America Interferometric Synthetic Aperture Radar consortium.

In terms of organizational structures, and the ability to be nimble and to partner with other organizations, Aster offered that the current seismological and geodetic facilities are “extraordinarily efficient” in realizing data collection and utilization when compared to individual projects that are distributed by funding agencies to standalone researchers, even at well-supported universities. He noted that there is still potential for partnering with, for example, ocean science facilities, or for improving diversity in the Earth sciences. Aster summarized his presentation by stating that community engagement in facility management has resulted in sustained transparency, consensus vision, optimal facilities and resource use, mentorship of leadership within the community itself, and overall agility in the service of research, teaching, and broader impact goals.

MODERATED QUESTIONS AND ANSWERS

Multiple themes were raised during a question and answer session with Flesch and Aster. The sections below synthesize the major themes raised. Some of the discussion fell slightly outside the bounds of the workshop planning committee’s Statement of Task, but are included here to present a complete record of discussion themes.

2015 Community Workshop Topics

Flesch and Aster were asked how topics for the 2015 community workshop were chosen. Flesch responded that the organizing committee for that workshop received a skeleton outline of science topics from NSF. The organizing committee then solicited white papers from the technical community, which identified scientific community needs, revealed key questions to be asked, shaped the focus of workshop topics, and informed the workshop organization. The agenda of that workshop diverged from the charge given to the organizing committee so that the workshop could be optimally responsive to scientific community needs.

Data and Computing Challenges

When asked if data access and data management were becoming a bigger barrier and whether issues related to data were getting solved, Aster responded that there were multiple issues at various scales. Examples he provided include:

• deciding how much computational power would be needed for a particular investigation and how to make that computational power available to the investigators and their students;
• managing community software of varying quality that has been heavily customized;
• grassroots development efforts that are changing the way people do workflows;
• university issues (e.g., related to tapping into regional supercomputers); and
• professional support (e.g., specialized groups that can handle data structures and programming of calculations for full-waveform seismic inversion).

Aster indicated that a lot of work remains to democratize access to computing capabilities.

Another workshop participant added that some investigations generate or compute terabytes of data per day, and that the common model in which data are distributed to users will not scale to need in the near future. It might be appropriate in the next 5 to 10 years to think beyond democratizing computing, and to move analysis closer to where the data are, the participant continued. Aster agreed and stated that the community is considering how to manage massive data sets such as those from distributed acoustic sensing technology and large experiments involving thousands of seismographs. Flesch added that data from the GNSS and from interferometric synthetic aperture radar (InSAR) can be large and provide management challenges.

Partnerships

In response to a question about the Incorporated Research Institutions for Seismology (IRIS) and UNAVCO aspirations to form partnerships with agencies other than NSF, Aster stated that both facilities have a record of working adaptively and collaboratively with other agencies, such as the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration. The partnerships are often driven by opportunities that arise—for example, IRIS promoting seismology on Mars—but they might also arise synergistically. Aster gave the example of the longstanding Central and Eastern U.S. Seismographic Network established by IRIS. That network has been transferred completely to the USGS for long-term seismic studies in the Eastern United States.

Unanticipated Science Emerging from Facilities

When asked if there are examples of revolutionary science that are the result of capabilities offered by current seismological and geodetic facilities, Flesch provided the example of how a Global Positioning System (GPS) campaign at the Cascadia Subduction Zone resulted in the discovery of phenomena at multiple temporal scales that ultimately informed science in unexpected ways. Initially, it was thought that GPS data in Cascadia would allow researchers to measure plates moving at a constant velocity, but instead the campaign revealed slow slip events¹ on the Cascadia Subduction Zone. As a result of that discovery, permanent stations were established to monitor the phenomena.

Integrating Earth and Ocean Science Capabilities

Multiple workshop participants questioned why IRIS and UNAVCO did not support marine seismic research. Aster agreed that there is less understanding of the tectonic and process significance of oceanic plates and earthquakes versus terrestrial plates and earthquakes, and that there is a strong scientific motivation to think about seismology from a global perspective. He stated that less instrumentation in the oceans corresponds

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¹ Slow slip events, also called episodic tremor and slip, are ground motions that occur along subduction zone boundaries over a period of time (weeks/months/years). The movement occurs at slower rates than traditional earthquakes, and can propagate over the length of the subduction zone. It is believed that slow slip events may increase stress on sections of the subduction and trigger a larger earthquake event. Slow slip events have been occurring approximately every 14 months along the Cascadia Subduction Zone in Washington State. See https://www.iris.edu/hq/inclass/fact-sheet/episodic_tremor_and_slip.

to missed opportunities. A workshop participant stated that a global seismic network was a worthy goal, and other participants described the potential for scientific and technical synergies between the land and marine seismic communities. A workshop participant observed that a better understanding about the fundamental tectonic structure of Earth and its crustal plates would only be possible with a greatly expanded ability to make seismic measurements in the ocean. Aster indicated that there were organizational boundaries within NSF that would need to be addressed before such collaborative work could be undertaken. Patino acknowledged this statement and stated that similar organizational boundaries exist elsewhere. As an example, she mentioned the management boundaries that prevent those working on earthquake scientific issues, earthquake early warning efforts, and earthquake mitigation efforts to collaborate formally. Maggie Benoit, the NSF program director for the Seismological Facility for the Advancement of Geoscience (SAGE) and the Geodetic Facility for the Advancement of Geoscience (GAGE), indicated her appreciation of the comments, and that efforts for greater cooperation were being made at NSF.