The Central and Eastern United States (CEUS) is a high-impact, low-probability (HI-LP) region with zones of moderate earthquake activity compared to that of plate boundary regions. Given the complex seismotectonics of this intraplate region, the CEUS earthquake hazard is generally not well understood or appreciated by the population. And yet, moderate-size to large and damaging earthquakes, with strong ground shaking felt over wide areas, have occurred in this region, such as in: Cape Ann, MA (1755, M~6.2), New Madrid, MO (1811-1812, M~7.1, 7.2), and Charleston, SC (1886, M~7.0). These and other more recent CEUS earthquakes occurred in places not easily explained by plate tectonics. Although seismologists only partially understand why these earthquakes occur where they do, people in impacted communities want to know why they are occurring and what their implications are for living in the CEUS. Providing local communities vulnerable to CEUS HI-LP earthquakes with high-quality science information, along with delivering honest messages about the uncertainties, is thus the big challenge for seismologists working on CEUS earthquake problems.

 

For this Pilot Project, we investigate these issues through targeted studies of currently active seismicity in the Southeastern and Northeastern United States regions (SEUS and NEUS). Through these targeted studies, we will be exploring fundamental earthquake science questions that are of importance to understanding and mitigating earthquake hazards in the CEUS, such as: To what extent are intraplate earthquakes different from plate boundary earthquakes? How are intraplate earthquakes related to mapped faults and other pre-existing structures? Is the spatial pattern of seismicity in intraplate regions generally persistent over time (or does it vary significantly over time)?

 

Community science collaboration with research seismologists based on the use of community seismographs has been recently promoted for augmenting (typically more sparsely distributed) long-term research-grade networks (e.g., Calais et al., 2019; Zaharia et al., 2023). Examples of creative use of new types of low-cost seismographs are: “The Quake Catcher” network of accelerometers (e.g., Cochran, 2018), seismic signals recorded by fiber optic cables (e.g., Lindsey and Martin, 2021), Raspberry Shakes (RSs, e.g., Anthony et al., 2019), and autonomous All-In-One “nodal” seismic systems (e.g., Karplus and Schmandt, 2018). But to what extent are these low-cost community science and nodal instruments truly useful for answering our fundamental science questions regarding earthquake hazards in the CEUS? In this Pilot Project, we explore the utility of RSs and nodes for augmenting long-term research-grade networks.

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RSs are, for example, being promoted for densifying research grade networks to provide better detection of small earthquakes and improved locations of larger earthquakes, but what are their limitations? A case in point regarding RS limitations is that siting of community seismographs is often less-than-ideal because it comes with a combined agenda of wanting a quiet site while encouraging community engagement in the work of understanding and mitigating local earthquake hazards. We usually think of seismographs as recording earthquakes, which of course they do, but they also record lots of other things that “shake”, such as activities of people and vehicle traffic near the seismograph site, storms, snow plows, wind turbines, aircraft, construction sites, thunder, washing machines, and more. In the case of typical research seismographs, we try to install them in seismically quiet places so that earthquake signals won’t be obscured by signals from other sources of seismic waves.

 

Educational and community seismographs, by contrast, can be quite noisy because they are often purposely installed near people and other human cultural noise sources. Thus, many RS sites are in locations that are convenient for community science research partners but seismically noisier than research seismologists prefer. And yet, this is not necessarily an inherent problem with RSs; some RS community sites are very quiet, most are in between, and some are very noisy. And, research quality siting is not the only criterion for assessing the value of community seismographs. We want our educational and community seismographs to be near where the people are so that people can interact with them directly. That can be a problem for seismic monitoring of earthquakes, but it’s not always bad for other aspects of seismology. (e.g., Lecocq et al, 2020; Kafka et al., 2022; raspberryshake.org, 2023). There are two complementary aspects of community seismographs: research and community engagement.

 

We are exploring the strengths and weaknesses of RSs, combined with data from time-limited deployment of All-in-One “nodal” systems and from permanent broadband sites, for addressing our CEUS earthquake science research questions. RSs have recorded earthquake data, often quite well, in the ~0.1 to ~45 Hz frequency range (e.g., see Twitter.com/Weston_Quakes). In the higher-frequency part of that range, RSs can be quite useful for densifying regional earthquake monitoring networks (e.g., Anthony et al., 2019), thus contributing to addressing key components of our CEUS research questions. Nodes have a somewhat higher-frequency range of recording than RSs, but they are useful for monitoring in the frequency bands associated with local and regional earthquake monitoring. Several recent studies also utilized teleseismic data recorded by nodes for receiver functions and other types of seismic imaging (e.g., Schmandt and Clayton, 2013). RSs are designed for long-term operation, dependent only on the availability of a standard electrical outlet and access to the internet. Nodes are more limited in duration of deployment, due to their being dependent on battery power, which typically lasts for about 30 days before needing to be recharged. A recent updated version of the SmartSolo node allows up to 120 days of continuous recording with an external battery pack, which provides much longer time of temporal coverage (e.g., Peng et al., 2023). Thus, RSs and nodes have advantages and disadvantages for monitoring the range of types of earthquakes we are likely to encounter in this Pilot Project.

 

And, even though RSs and nodes might not always be the ideal instruments for seismological research, they still, nonetheless, contribute to the community engagement aspects of this Pilot Project, and of C-CIES in general. For example, community science partners who operate and/or support operation of RSs and nodes, experience real science (beyond the textbook and media depiction of science) and hence become more scientifically educated citizens, with an improved understanding of science-based public policy issues.

 

Contemporary technological interventions such as the Raspberry Shakes are the modern iteration of long-standing attempts by non-experts to create usable explanations for why the ground sometimes moves. From eggs hung from a string during the aftershocks of the New Madrid earthquakes of 1811-12 to newspaper accounts of bodily sensation during the San Francisco earthquake of 1906, human beings have long attempted to come up with ways to document and come to terms with alarming seismic phenomena (Valencius, 2013). Our pilot project asks how we can harness that historic interest in engaging with “visibility” and measurement in ways that promote scientific awareness, observation, and conversation.

 

To begin addressing these issues, we will explore the extent to which RSs and nodal deployments can be helpful in augmenting (typically more sparsely distributed) long-term research-grade networks and thus contribute to resolving CEUS scientific questions and to mitigating public unease regarding CEUS earthquakes that occur in “surprising” locations. We will use RS community seismographs, as well as autonomous All-In-One high-frequency seismic systems, such as Zland 3C nodes and/or SmartSolo 3C units to explore the extent to which these various types of instruments compare and contrast in their utility as research, community science, and community engagement tools.

We will deploy RS and nodal instruments at locations in the SEUS and NEUS where there has been recent seismicity, and where we expect there to be a good chance of catching that activity in action. For these deployments, we will prefer sites where the instruments can be hosted by community scientists who want to be involved in the community engagement aspects of C-CIES. We, of course, realize the risk that the activity in our target locations might cease and we will record few (if any) earthquakes there. While that would be disappointing, C-CIES is not a typical NSF-funded project: it explicitly combines its scientific objectives with community engagement. Thus, even if we don’t catch an active earthquake process in action, we would nonetheless still be engaged with local communities in earthquake monitoring (e.g., Zaharia et al., 2023; Calais et al., 2019).

 

RSs are designed for long term, “permanent” recording (i.e., for as long as a person is willing to host the site). Community scientists participating with us would be able to continue to access RS data (indefinitely) from the CEUS and around the world through user friendly RS web, desktop, and mobile apps (both Android and iOS). With a relatively short learning curve, those apps are generally intuitive to use for educational and community science purposes. And, for research purposes the RS data can be easily accessed from the RS server, using standard software in common use by research seismologists.

 

The current RS global network includes more than 2,000 stations streaming live seismic data across the globe. Many of those stations are located at sites in the CEUS that can be incorporated into this Pilot Project. We could include RS sites with the nodal deployments, and after the nodal deployments are completed, leave them there for long term monitoring of those locations where we know there has been significant activity in the recent past. And, even if we don’t record much earthquake activity in our targeted regions, our RSs will undoubtedly record other seismic phenomena that community science partners would find interesting. It's very likely, for example, that we will record interesting teleseisms and larger CEUS regional events, will record local noise and other local events of interest, and will be able to test the quality of the RS and nodal siting conditions. Thus, the low-cost seismograph deployments of this Pilot Project would support the community engagement aspects of C-CIES, and are likely to yield useful data regarding our fundamental science questions about earthquake processes and hazards in the CEUS.

 

 

References:

 

Anthony, R.E., A.T. Ringler, D.C. Wilson, and E. Wolin (2019). Do low-cost seismographs perform well enough for your network? an overview of laboratory tests and field observations of the OSOP Raspberry Shake 4D, Seism. Res. Lett., 90 (1), 219-228, doi: 10.1785/0220180251

 

Calais, E., D. Boisson, S. Symithe, R. Momplaisir, C. Prépetit, S. Ulysse, G.P. Etiene, F. Courboulex, A. Deschamps, T. Monfret, J. Ampuero, B. Mercier de Lépinay, V. Clouard, R. Bossu, L. Fallou, and E. Bertrand (2019), Monitoring Haiti’s quakes with Raspberry Shake, EOS, 100, doi: 10.1029/2019EO123345.

 

Cochran, E.S. (2018), To catch a quake, Nat Commun 9, 2508, doi: 10.1038/s41467-018-04790-9.

Kafka, A.L., J.J. Pulli, K.R. Fink, C. Stapels, K. Cannon, D. McCasland, K. McLaughlin, R. Block, Stephen R. McNutt, J. N. Kafka, M. J. Sharkey (2022). That's the way the Raspberry Shakes: 2022 update on the intriguing variety of things we record with Shakes and Booms, Abstract and poster presented at: Eastern Section Meeting, Seismological Society of America, Tampa, FL, October 23-25, 2022. Also see related blog here.

 

Karplus, M. and B. Schmandt (2018), Preface to the Focus Section on Geophone Array Seismology, Seismological Research Letters, 89(5), 1597–1600. doi.org/10.1785/0220180212

 

Lindsey, N.J., and E.R. Martin (2021), Fiber-optic seismology. Annual Review of Earth and Planetary Sciences, 49(1), 309–336, doi.org/10.1146/annurev-earth-072420-065213.

 

Lecocq, et al., with 75 coauthors from around the world (2020). Global Quieting of High-Frequency Seismic Noise Due to COVID-19 Pandemic Lockdown Measures, Science, 10.1126/science.abd2438.

 

Peng, Z., L.Y. Chuang, P. Mach, D. Frost, S. Howard and S. White (2023). High-Resolution Imaging of the Elgin-Lugoff Earthquake Swarm Sequence in South Carolina Using a Dense Seismic Nodal Array. Seismo. Res. Lett., 94(2b), 1280. Abstract presented at the 2023 Seismological Society of America Annual Meeting, San Juan, PR, 17-20, April.

 

raspberryshake.org (2023). From Data to Discovery: How Raspberry Shake is Empowering Open Science, Retrieved 05/10/2023 from https://raspberryshake.org/news/open-science.

 

Schmandt B., and Clayton R. 2013. Analysis of teleseismic P waves with a 5200‐station array in Long Beach, California: Evidence for abrupt boundary for Inner Borderland rifting, J. Geophys. Res.  118, 1–19, doi.org/10.1002/jgrb.50370.

Valencius, CB. 2013. The Lost History of the New Madrid Earthquakes. University of Chicago Press.

 

Zaharia, B., Grecu, B., Tolea, A., M. Radulian (2023). Seismic observations in Bucharest area with a Raspberry Shake citizen science network. Appl. Sci., 13, 5646, doi.org/10.3390/ app13095646