Geology topics

Stacey S. Martin

Publications and source records attributed to Stacey S. Martin.

8 recordsLinked to original sources

USGS2022

Rupture scenarios for the 3 June 1770 Haiti earthquake

The 2010 M 7.0 Haiti earthquake provided the impetus to reconsider historical earthquakes in Hispaniola ( Bakun et al. , 2012 ). That earthquake also shed new light on complex fault systems along Haiti’s southern peninsula ( Douilly et al. , 2013 ; Saint Fleur et al. , 2015 ). Recently, the 2021 M 7.2 Nippes earthquake ( Calais et al. , 2022 ; Douilly et al. , 2022 ), and a recent study reconsidering the 1860 sequence ( Martin et al. , 2022 ) further underscored the complexity of fault systems and large earthquake ruptures along the peninsula. Motivated by these studies and recent geological investigations ( Prentice et al. , 2010 ; Saint Fleur et al. , 2020 ), we reconsider the 3 June 1770 Haiti earthquake to explore the conventional assumption that it was the last major ( M ≥7.5) earthquake along the Enriquillo–Plantain Garden fault (EPGF). Accounts provide compelling evidence for substantial liquefaction in the Cul‐de‐Sac plain, one or more likely landslide‐driven tsunami in Gonaïves Bay, and extensive landsliding that created at least three documented landslide dams. We consider three end‐member rupture scenarios that are consistent with available constraints: two scenarios with M 7.7 and rupture lengths of 150–170 km, and one scenario with a ∼90 km rupture and M 7.5. Absent future work to identify and date paleoevents along the southern peninsula, none of these scenarios can be ruled out. Our preferred rupture model extends from the Miragoâne pull‐apart to near la Selle mountain, with a rupture length of 127 km, M 7.6, and a high stress drop. Rupture could have been on the EPGF or on an oblique thrust fault associated with overthrusting of the Massif de la Selle. The results do support the conclusion that the 1770 earthquake was the last major earthquake in southern Haiti, with a magnitude upward of M 7.5 and significantly more severe shaking in southern Haiti than during the 2010 earthquake.

Bulletin of the Seismological Society of America↗

USGS2021

Reply to “comment on ‘which earthquake accounts matter?’ by Susan E. Hough and Stacey S. Martin” by David J. Wald

We thank David Wald ( Wald, 2021 ; henceforth, W21) for his interest in our recent article ( Hough and Martin, 2021 ; henceforth, HM21). Although different perspectives are vital in science, we are concerned that W21 misrepresents HM21 as an oblique criticism of the U.S. Geological Survey “Did You Feel It?” (DYFI) system, calling for HM21 to be retracted. Readers who are interested in the issues raised by HM21 and the statements made by us therein are referred to that article. In this brief reply, we respond to specific accusations made by W21 and return to the focus of HM21, calling attention to the extent to which macroseismic data sets and inferences drawn from them can be shaped by a lack of representation among individuals whose observations are available to science. HM21 never questioned the benefits of the community science DYFI project to science. HM21 noted, however, and we reiterate here, that community science also potentially benefits the community. Whether or not it matters for science, if participation in community science projects is unrepresentative across socioeconomic groups, it underscores the need for the scientific community to be proactive in its efforts to reach out to groups that have been underserved by current outreach and education programs. We appreciate this opportunity to continue the important conversation about representation.

Seismological Research Letters↗

USGS2021

Which earthquake accounts matter?

Earthquake observations contributed by human observers provide an invaluable source of information to investigate both historical and modern earthquakes. Commonly, the observers whose eyewitness accounts are available to scientists are a self‐selected minority of those who experience a given earthquake. As such these may not be representative of the overall population that experienced shaking from the event. Eyewitness accounts can contribute to modern science only if they are recorded in the first place and archived in an accessible repository. In this study, we explore the extent to which geopolitics and socioeconomic disparities can limit the number of earthquake observers whose observations can contribute to science. We first revisit a late nineteenth‐century earthquake in the central United States in 1882 that provides an illustrative example of an event that has been poorly characterized due to a reliance on English‐language archival materials. For modern earthquakes, we analyze data collected for recent earthquakes in California and India via the online “Did You Feel It?” (DYFI) system. In California, online data‐collection systems appear to be effective in gathering eyewitness accounts from a broad range of socioeconomic groups. In India, however, responses to the DYFI system reveal a strong bias toward responses from urban areas as opposed to rural settlements, as well a bias with literacy rate. The dissimilarity of our results from modern earthquakes in the United States and India provides a caution that, in some parts of the world, contributed felt reports can still potentially provide an unrepresentative view of earthquake effects, especially if online data collection systems are not designed to be broadly accessible. This limitation can in turn potentially shape our understanding of an earthquake’s impact and the characterization of seismic hazard.

Arkansas, Oklahoma, Texas↗

USGS2019

Where was the 31 October 1895, Charleston, Missouri Earthquake?

We revisit the magnitude and location of the 31 October 1895 Charleston, Missouri earthquake, which is widely regarded to be the last M W 6 or greater earthquake in the central United States. Although a recent study (Bakun et al., 2003) concluded that this earthquake was located in southern Illinois, over 100 km north of the traditionally inferred location near Charleston, Missouri, our analysis of exhaustively compiled macroseismic data supports the traditionally inferred location, with a preferred magnitude of M W ≈ 5.8, and preferred range of 5.4 to 6.1. Our preferred magnitude is derived from comparisons with intensity distributions from the 1925 M W = 6.2 Charlevoix, the 1944 M W = 5.8 Massena, and the 1968 M W = 5.3 southern Illinois earthquakes, which we also revisited in this study. Based on the distribution of liquefaction, reports of damage, and early aftershocks, we also explore possible rupture scenarios for the 1895 earthquake. Our preferred scenario involves unilateral rupture to the northeast on a (reactivated) northeast-striking fault (or faults) coinciding with structures associated with the western limb of the Reelfoot Rift, with an epicenter south-southeast of Charleston, Missouri. Our results support the conclusion that, within the Reelfoot Rift, elevated seismic hazard is not restricted to the New Madrid Seismic Zone (NMSZ) as conventionally defined but continues into the Charleston region in southeastern Missouri where faults associated with the western edge of the Reelfoot Rift appear favorably oriented for failure in the current stress regime.

Missouri↗

USGS2018

A proposed rupture scenario for the 1925 Mw 6.5 Santa Barbara, California, earthquake

The 29 June 1925 Santa Barbara earthquake is among the largest 20th century earthquakes in southern California. The earthquake also predated the installation of strong motion and local monitoring instruments in southern California; some instrumental data are, however, available from long-period instruments at regional and teleseismic distances. The current catalog moment magnitude is M W 6.8. Initial intensity magnitudes (M I ) estimated from original Coast and Geodetic Survey intensity assignments were lower (M I 6.3). In this study we assign modified Mercalli intensity values at 239 locations, including 144 specific locations within the city of Santa Barbara for which detailed damage information is available. Comparing the reinterpreted intensities with Did You Feel it? intensities for recent events in California, we estimate M W = 6.5, with a plausible range of 6.3–6.6. We further consider reported instrumental amplitudes to estimate an instrumental moment magnitude of M W = 6.6 ± 0.5. Our preferred final estimate is M W 6.5. Based on available constraints including aftershock locations inferred from data recorded on portable instruments, we propose that the earthquake nucleated east of the city of Santa Barbara, closer to the coast than previously estimated, and ruptured unilaterally ~30 km to the west, possibly along the south-dipping Mesa-Rincon Creek, and the More Ranch fault systems. Contrary to suggestions made in earlier studies (e.g. Willis, 1925a), relatively high intensities ~50 km west of Santa Barbara can then be explained by directivity rather than involvement of the Santa Ynez fault. Finally, we discuss the possibility that the earthquake was triggered by the larger M W = 6.6 Clarkston, Montana earthquake the previous day or induced by oil production in the Summerland oil field.

California↗

USGS2016

Thumbnail‐based questionnaires for the rapid and efficient collection of macroseismic data from global earthquakes

The collection of earthquake testimonies (i.e., qualitative descriptions of felt shaking) is essential for macroseismic studies (i.e., studies gathering information on how strongly an earthquake was felt in different places), and when done rapidly and systematically, improves situational awareness and in turn can contribute to efficient emergency response. In this study, we present advances made in the collection of testimonies following earthquakes around the world using a thumbnail‐based questionnaire implemented on the European‐Mediterranean Seismological Centre (EMSC) smartphone app and its website compatible for mobile devices. In both instances, the questionnaire consists of a selection of thumbnails, each representing an intensity level of the European Macroseismic Scale 1998. We find that testimonies are collected faster, and in larger numbers, by way of thumbnail‐based questionnaires than by more traditional online questionnaires. Responses were received from all seismically active regions of our planet, suggesting that thumbnails overcome language barriers. We also observed that the app is not sufficient on its own, because the websites are the main source of testimonies when an earthquake strikes a region for the first time in a while; it is only for subsequent shocks that the app is widely used. Notably though, the speed of the collection of testimonies increases significantly when the app is used. We find that automated EMSC intensities as assigned by user‐specified thumbnails are, on average, well correlated with “Did You Feel It?” (DYFI) responses and with the three independently and manually derived macroseismic datasets, but there is a tendency for EMSC to be biased low with respect to DYFI at moderate and large intensities. We address this by proposing a simple adjustment that will be verified in future earthquakes.

Seismological Research Letters↗

USGS2016

A comparison of observed and predicted ground motions from the 2015 M W 7.8 Gorkha, Nepal, earthquake

We use 21 strong motion recordings from Nepal and India for the 25 April 2015 moment magnitude (M W ) 7.8 Gorkha, Nepal, earthquake together with the extensive macroseismic intensity data set presented by Martin et al. (Seism Res Lett 87:957–962, 2015 ) to analyse the distribution of ground motions at near-field and regional distances. We show that the data are consistent with the instrumental peak ground acceleration (PGA) versus macroseismic intensity relationship developed by Worden et al. (Bull Seism Soc Am 102:204–221, 2012 ), and use this relationship to estimate peak ground acceleration from intensities (PGA EMS ). For nearest-fault distances (R RUP < 200 km), PGA EMS is consistent with the Atkinson and Boore (Bull Seism Soc Am 93:1703–1729, 2003 ) subduction zone ground motion prediction equation (GMPE). At greater distances (R RUP > 200 km), instrumental PGA values are consistent with this GMPE, while PGA EMS is systematically higher. We suggest the latter reflects a duration effect whereby effects of weak shaking are enhanced by long-duration and/or long-period ground motions from a large event at regional distances. We use PGA EMS values within 200 km to investigate the variability of high-frequency ground motions using the Atkinson and Boore (Bull Seism Soc Am 93:1703–1729, 2003 ) GMPE as a baseline. Across the near-field region, PGA EMS is higher by a factor of 2.0–2.5 towards the northern, down-dip edge of the rupture compared to the near-field region nearer to the southern, up-dip edge of the rupture. Inferred deamplification in the deepest part of the Kathmandu valley supports the conclusion that former lake-bed sediments experienced a pervasive nonlinear response during the mainshock (Dixit et al. in Seismol Res Lett 86(6):1533–1539, 2015 ; Rajaure et al. in Tectonophysics, 2016 . Ground motions were significantly amplified in the southern Gangetic basin, but were relatively low in the northern basin. The overall distribution of ground motions and damage during the Gorkha earthquake thus reflects a combination of complex source, path, and site effects. We also present a macroseismic intensity data set and analysis of ground motions for the M W 7.3 Dolakha aftershock on 12 May 2015, which we compare to the Gorkha mainshock and conclude was likely a high stress-drop event.

Gorkha District↗

USGS2016

Reply to “Comment on ‘Ground motions from the 2015 Mw 7.8 Gorkha, Nepal, earthquake constrained by a detailed assessment of macroseismic data’ by Stacey S. Martin, Susan E. Hough, and Charleen Hung” by Andrea Tertulliani, Laura Graziani, Corrado Castellano, Alessandra Maramai, and Antonio Rossi

We thank Andrea Tertulliani and his colleagues for their interest in our article on the 2015 Gorkha earthquake (Martin, Hough, et al., 2015), and for their comments pertaining to our study (Tertulliani et al., 2016). Indeed, as they note, a comprehensive assessment of macroseismic effects for an earthquake with far‐reaching effects as that of Gorkha is not only critically important but is also an extremely difficult undertaking. In the absence of a widely known web‐based system, employing a well‐calibrated algorithm with which to collect and systematically assess macroseismic information (e.g., Wald et al., 1999; Coppola et al., 2010; Bossu et al., 2015) in the Indian subcontinent, one is left with two approaches to characterize effects of an event such as the Gorkha earthquake: a comprehensive ground‐based survey such as the one undertaken in India following the 2001 Bhuj earthquake (Pande and Kayal, 2003), or an assessment such as Martin, Hough, et al. (2015) akin to other contemporary studies (e.g., Nuttli, 1973; Sieh, 1978; Meltzner and Wald, 1998; Martin and Szeliga, 2010; Ambraseys and Bilham, 2012; Mahajan et al., 2012; Gupta et al., 2013; Singh et al., 2013; Hough and Martin, 2015; Martin and Hough, 2015; Martin, Bradley, et al., 2015; Ribeiro et al., 2015), based primarily upon media reports and other available documentary accounts.

Seismological Research Letters↗