About

Patricia Persaud is an Associate Professor in the Department of Geosciences at the University of Arizona. Her research interests include earthquake ground motions, imaging high geo-hazards regions, underground storage for the energy transition, borehole stress, large-N seismic datasets, and machine learning methods for earthquake detection. She leads a research group focused on these areas, contributing to the understanding of seismic hazards and geophysical processes. Her work involves utilizing advanced seismic data analysis and imaging techniques to address critical issues related to geohazards and energy storage.

Research topics

• Geology
• Seismology
• Artificial Intelligence
• Data Mining
• Computer Science
• Geophysics
• Petrology
• Geodesy
• Paleontology
• Geomorphology
• Algorithm
• Geometry
• Remote sensing

Selected publications

• Receiver Functions in the San Fernando Valley, California: Graph-Regularized Bayesian Approach for Gravity-Informed Mapping

  ArXiv.org · 2026-01-05

  articleOpen accessSenior author

  The San Fernando Valley (SFV) in Southern California is a complex sedimentary basin whose shape strongly influences ground shaking. We develop a fully quantitative, probabilistic graph-regularized inference model that integrates both gravity and receiver function (RF) constraints and evaluate its ability to determine the basin's shape. The sediment-basement interface in single-station RFs is often difficult to interpret due to scattering and noise, which can render isolated stations unusable. By using RFs from a dense seismic array and incorporating gravity, we address the issue of non-uniqueness in converting the times of RF phases to layer thickness by comparing the predicted gravity to observations at each station. In areas where the density contrast may change, Bayesian inference with a graph Laplacian allows us to determine the effective density contrast by taking into account its neighbors' picks and densities. This method promotes spatial smoothness between neighboring stations, while preserving sharp contrasts in locations supported by the RF and gravity data. We applied this method to a dataset that was acquired in fall 2023, when 140 nodes were installed in the SFV. Our results show the deep Sylmar sub-basin, the San Fernando sub-basin, and the Leadwell high found in a previous study (Juárez-Zúñiga and Persaud, 2025), and our results also show good agreement with the industry seismic reflection profiles across the valley. This method demonstrates how to incorporate gravity with lateral density variations into receiver function interpretation to better map interfaces in the subsurface.

  PublisherOA PDF

• Receiver Functions in the San Fernando Valley, California: Graph-Regularized Bayesian Approach for Gravity-Informed Mapping

  arXiv (Cornell University) · 2026-01-05

  preprintOpen accessSenior author

  The San Fernando Valley (SFV) in Southern California is a complex sedimentary basin whose shape strongly influences ground shaking. We develop a fully quantitative, probabilistic graph-regularized inference model that integrates both gravity and receiver function (RF) constraints and evaluate its ability to determine the basin's shape. The sediment-basement interface in single-station RFs is often difficult to interpret due to scattering and noise, which can render isolated stations unusable. By using RFs from a dense seismic array and incorporating gravity, we address the issue of non-uniqueness in converting the times of RF phases to layer thickness by comparing the predicted gravity to observations at each station. In areas where the density contrast may change, Bayesian inference with a graph Laplacian allows us to determine the effective density contrast by taking into account its neighbors' picks and densities. This method promotes spatial smoothness between neighboring stations, while preserving sharp contrasts in locations supported by the RF and gravity data. We applied this method to a dataset that was acquired in fall 2023, when 140 nodes were installed in the SFV. Our results show the deep Sylmar sub-basin, the San Fernando sub-basin, and the Leadwell high found in a previous study (Juárez-Zúñiga and Persaud, 2025), and our results also show good agreement with the industry seismic reflection profiles across the valley. This method demonstrates how to incorporate gravity with lateral density variations into receiver function interpretation to better map interfaces in the subsurface.

  PublisherDOI

• Nature of the Crust in the Superdeep Bengal Basin Using Teleseismic P Waves

  Journal of Geophysical Research Solid Earth · 2026-03-01

  articleOpen access

  Abstract The Bengal Basin is a sedimentary basin in the northeast region of the Indian subcontinent. It lies between the Indian Shield and the Indo‐Burma Ranges, where the India plate is obliquely subducting under the Burma microplate. Multiple interpretations of the nature of the crust here have been proposed. Using a compilation of data from 40 regional broadband stations, we determine the crustal structure by waveform modeling receiver functions and autocorrelograms. We obtain useful velocity models for 30 stations with 2–3 sedimentary units overlying the crystalline crust. The sedimentary section is up to 16.4 km thick with depths increasing from northwest to southeast. The first two sedimentary units have mean thicknesses of ∼3.2 and ∼6.5 km and Vp values of ∼2.8 and ∼4.9 km/s, respectively. Below these units, large negative Ps conversions are present, which we interpret as two low‐velocity zones in the deepest portion of the Bengal Basin, with average Vp and Vp/Vs values of 4.2 km/s and 1.90. The low seismic velocities could be a result of fluids trapped in the deepest sedimentary unit. Below the sedimentary section the thickness of the crystalline crust varies from 12.9 to 34 km, thinning from northwest to southeast in the opposite general trend of basin depth, with an average Vp of 6.7 km/s. The crystalline crust is thinner and faster than typical continental crust and thicker and slower than typical oceanic crust. We suggest the region has extended continental crust that was altered during the Cretaceous rifting that created the Bengal Basin.

  PublisherDOI

• A slab’s journey from subduction to collision: Lithospheric structure of Myanmar from finite-frequency tomography

  2025-03-15

  preprintOpen accessSenior author

  Myanmar is located south of the Eastern Himalayan Syntaxis, where tectonic activity is driven by the northward indentation of the Indian Plate into Asia and the oblique eastward subduction of India beneath the western margin of the Burmese microplate. Dextral motion along the Sagaing Fault separates the eastern margin of the Burmese microplate from the Asian Plate. The associated lithospheric structure is complex and three-dimensional, featuring a transition from an oceanic-transitional subduction slab to continental subduction and collision, likely involving plate tearing and bending. Additionally, intermediate-depth seismicity and volcanism are linked to processes associated with the ongoing subduction. We use finite-frequency teleseismic P-wave tomography to explore the relationship and interaction of these different tectonic elements. Our input data is derived from approximately 480 teleseismic earthquakes that occurred between 2019 and 2021, recorded by around 140 regional seismic stations, primarily from temporary deployments. These include stations of the 6C (2018–2022, MySCOLAR) network, operated by GFZ and DMH, and the XR (2018–2022, Tripartite BIMA) network, operated by the University of Missouri with partners, as well as stations deployed by the Earth Observatory of Singapore (EOS). The dataset is further augmented by permanent stations from the China National Seismic Network (SEISDMC), the Geophysical Broadband Observation Network (GEOFON), and other regional permanent stations accessible through the Incorporated Research Institutions for Seismology (IRIS). Travel-time residuals were calculated via cross-correlation in three frequency bands (0.1, 0.3, and 0.5 Hz central frequency). The resulting P-wave velocity models are derived from around 70,000 residuals, covering the area between 90° to 101°E and 18° to 30°N, down to approximately 600 km depth. Data coverage and resolution are best in central and northern Myanmar. This enables the illumination of the geometry and characteristics of the different lithospheric units involved in the subduction/collision transition and slab bending towards the Eastern Himalayan Syntaxis.

  PublisherDOI

• Monitoring Salt Domes Used for Energy Storage with Microseismicity: Insights for a Carbon-Neutral Future

  2025-02-04

  preprintSenior author

  Underground storage in geologic formations will play a key role in the energy transition by providing low-cost storage of renewable fuels like hydrogen. The sealing qualities of caverns leached in salt and availability of domal salt bodies make them ideal for energy storage. However, unstable boundary shear zones of anomalous friable salt can enhance internal shearing and pose a structural hazard to storage operations. Considering the indistinct nature of internal salt heterogeneities when imaged with conventional techniques like reflection seismic surveys, we develop a method to map shear zones using seismicity patterns in the US Gulf Coast, the region with the world’s largest underground crude oil emergency supply. We developed and finetuned a machine learning algorithm using tectonic and local microearthquakes. The finetuned model was applied to detect microearthquakes in a 12-month nodal seismic dataset from the Sorrento salt dome. Clustered microearthquake locations reveal the three-dimensional geometry of two anomalous salt shear zones and their orientations were determined using probabilistic hypocenter imaging. The seismicity pattern, combined with borehole pressure measurements, and sonar surveys show the spatio-temporal evolution of cavern shapes within the salt dome. We describe how shear zone seismicity contributed to a cavern well failure and gas release incident that occurred during monitoring. Our findings show that caverns placed close to shear zones are more susceptible to structural damage. We propose a non-invasive technique for mapping hazards related to internal salt dome deformation that can be employed in high-noise industrial settings to characterize salt domes used for storage.

  PublisherDOI

• Evolving Sediment Structure and Lithospheric Architecture Across the Indo‐Burman Forearc Margin From the Joint Inversion of Surface‐ and Scattered‐Wave Seismic Constraints

  Journal of Geophysical Research Solid Earth · 2025-06-01 · 1 citations

  articleOpen access

  Abstract The Indo‐Burman subduction zone represents a global endmember for extreme sediment accretion and is a region characterized by ambiguous tectonic structure. The recent collection of broadband seismic data across the Indo‐Burman accretionary margin as part of the Bangladesh‐India‐Myanmar Array (BIMA) experiment provides an opportunity to investigate the subsurface velocity structure across the incoming plate of an endmember subduction system. We construct a three‐dimensional model for seismic shear velocity using a joint inversion of surface‐ and scattered‐wave constraints. Rayleigh‐wave phase velocities measured from ambient‐noise (12–25 s) and teleseismic earthquakes (20–80 s) constrain absolute shear velocities, while we constrain the locations of and relative contrasts across significant discontinuities in the subsurface using observations from scattered‐wave imaging. From the resulting inversion, we observe two model classes that characterize the evolution of consolidation within the markedly slow uppermost sediments and metasediments along a predominantly southwest‐to‐northeast trend. We interpret variations in deeper seismic structure under two proposed scenarios: (a) a Moho of ∼21–26 km depth underlying a package of metasediments and a thinned basement component, with a slow mantle lithosphere (4.2 km/s) that may contain retained melt from the onset of India‐Antarctica seafloor spreading; or (b) a Moho of ∼51–59 km depth underlying a package of metasediments, basement, and a thick slug of mafic material, which may correspond to significant Kerguelen‐plume‐related underplating. By combining constraints from highly resolved phase‐velocity estimates and scattered‐wave images, we successfully characterize the lateral transitions across the Indo‐Burman forearc margin.

  PublisherOA PDFDOI

• Detecting Urban Earthquakes with the San Fernando Valley Nodal Array and Machine Learning

  Seismological Research Letters · 2025-08-22

  articleOpen accessSenior author

  Abstract The San Fernando Valley (SFV), part of the Los Angeles metropolitan area, is a seismically active urban environment. Large-magnitude earthquakes, such as the 1994 Mw 6.7 Northridge event that occurred on a blind fault beneath the valley, caused significant infrastructure damage in the region, underscoring the need for enhanced seismic monitoring to improve the identification of buried faults and hazard evaluation. Currently, the Southern California Earthquake Data Center operates four broadband instruments within the valley; however, the network’s ability to capture small earthquakes beneath the region may be limited. To demonstrate how this data gap can be filled, we use recordings from the SFV array, comprised of 140 nodal instruments with interstation distances ranging from 0.3 to 2.5 km that recorded for one month. High-anthropogenic noise levels in urbanized areas tend to conceal earthquake signals; therefore, we applied a previously developed machine learning model fine-tuned on similar waveforms to detect events and pick seismic phases. In a two-step event association workflow, isolated phase picks were first culled, which eliminated false positive detections and reduced computational runtime. We located 62 events within a 209 km radius of our array with magnitudes ranging from ML 0.13 to 4, including 36 new events that were undetected by the regional network. One event cluster reveals a previously unidentified (5.3 km × 4 km) blind fault zone located ∼5 km beneath the southern part of the valley. Seismicity from this zone is rare in the regional catalog (<3 events per year), despite producing a Mb 4.4 event in 2014. Our results highlight the benefits of detecting small-magnitude seismicity for hazard estimation. Temporary nodal arrays can identify critical gaps in regional monitoring and guide site selection for permanent stations. In addition, our workflow can be applied to complement seismic monitoring in other urban settings.

  PublisherOA PDFDOI

• Nature of the crust in the superdeep Bengal basin using teleseismic P waves

  2025-02-09 · 2 citations

  preprintOpen access

  The Bengal basin is a sedimentary basin in the northeast region of the Indian subcontinent. It lies between the Indian Shield and the Indo-Burma Ranges, where the India plate is obliquely subducting under the Myanmar microplate and different interpretations of the nature of the underlying crust have been proposed. Using a compilation of data from 42 broadband stations in the region, we determine the crustal structure by waveform modeling receiver functions and vertical autocorrelograms. We obtain useful models for 30 stations with two or three sedimentary layers overlying the crystalline crust. Basin depths range from 8-21 km with depths increasing from northwest to southeast. The first two layers have mean thicknesses of ~3.5 km and ~8.2 km and Vp values of ~3.0 and ~6.0 km/s, respectively. Below these layers, large negative Ps conversions are present, which we interpret to be two low-velocity zones in the deepest portion of the basin, with average Vp and Vp/Vs values of 4.1 km/s and 1.91, respectively. The low velocities could be a result of fluids trapped in the sedimentary layers. Below the basin the thickness of the crystalline crust varies from 14 to 31 km, thinning from northwest to southeast in the opposite general trend of basin thickness, with an average Vp of 6.8 km/s. The crust is therefore thinner and faster than typical continental crust and thicker and slower than typical oceanic crust. We suggest the region has extended continental crust that was altered during the Cretaceous rifting that created the Bengal basin.

  PublisherOA PDFDOI

• New Insights into the Crustal Structure of the San Fernando Valley, California, from a Dense Nodal Seismic Array

  Seismological Research Letters · 2025-05-28 · 4 citations

  articleOpen accessSenior author

  Abstract The San Fernando Valley (SFV), a densely populated region in Southern California, has high earthquake hazard due to a complex network of active faults and the amplifying effects of the sedimentary basin. Since the devastating 1994 Mw 6.7 Northridge earthquake, numerous studies have examined its structure using various geological and geophysical datasets. However, current seismic velocity models still lack the resolution to accurately image the near-surface velocity structure and concealed or blind faults, which are critical for high-frequency wavefield simulations and earthquake hazard modeling. To address these challenges, we develop a 3D high-resolution shear-wave velocity model for the SFV using ambient noise data from a dense array of 140 seismic nodes and 10 Southern California Seismic Network stations. We also invert gravity data to map the basin geometry and integrate horizontal-to-vertical spectral ratios and aeromagnetic data to constrain interfaces and map major geological structures. With a lateral resolution of 250 m near the basin center, our model reveals previously unresolved geological features, including the detailed geometry of the basin and previously unmapped structure of faults at depth. The basin deepens from the Santa Monica Mountains in the south to approximately 4 km near its center and 7 km in the Sylmar sub-basin at the basin’s northern margin. Strong velocity contrasts are observed across major faults, at the basin edges, and in the basin’s upper 500 m, for which we measure velocities as low as 200 m/s. Our high-resolution model will enhance ground-motion simulations and earthquake hazard assessments for the SFV and has implications for other urban areas with high seismic risk.

  PublisherOA PDFDOI

• Estimating site amplification variability in Yangon, Myanmar, from a dense nodal seismic array

  Earthquake Spectra · 2025-07-11 · 3 citations

  articleOpen access

  We explore a novel acquisition geometry that can be used to estimate the linear component of site amplification using a dense nodal seismic network installed in Yangon, Myanmar’s largest city. The city is surrounded by several seismically active faults, including the Sagaing Fault, which is capable of generating M w > 7.0 earthquakes. As part of the Irrawaddy delta system, this densely populated city sits on young water-saturated alluvium that is likely to amplify earthquake ground motions. Assessing site response is crucial for understanding the seismic hazard potential to minimize the loss of property and lives. Using a dense seismic array comprised of 110 three-component nodes, we estimated the frequency-dependent site amplification pattern of Yangon from regional (Lg) and local (Sg) seismic phases. Since this acquisition geometry is not sensitive to Q or geometric spreading, this approach provides a fast and cost-effective way to estimate the linear component of site response as a function of frequency. Our Lg and Sg site response results identify regions with high site amplification that have significantly greater seismic hazard risks for regional and local distance earthquakes. We observed consistent site response characteristics between both Lg and Sg phases. Site amplification patterns correlate well with the surficial geology and subsurface structure beneath the city. De-amplification is observed across all frequencies at stations located above an anticlinal structure composed of older Pliocene rocks (i.e. the Irrawaddy Formation). Conversely, highly amplified areas correspond to younger Pleistocene to recent alluvial plains consisting of loose, unconsolidated alluvium. We found a dominant horizontal-to-vertical spectral ratio (HVSR) peak at ∼1.0 Hz from ambient noise, likely corresponding to the thickness of unconsolidated sediments. We suggest that the growing number of nodal networks worldwide can be used to estimate frequency-dependent site amplification, addressing key data gaps in seismic hazard assessment.

  PublisherDOI

Recent grants

• CAREER: Fluid-driven Deformation in Underground Salt Caverns and Wastewater Injection Sites

  NSF · $503k · 2021–2024

• Collaborative Research: Subduction below extreme sedimentation - A multidisciplinary transect from the Ganges-Brahmaputra Delta to the IndoBurma Backarc

  NSF · $331k · 2017–2023

• Collaborative Research: A New 3-D Velocity and Structural Model of the Northern Basins in the Los Angeles Region for Improved Ground Motion Estimates

  NSF · $205k · 2021–2023

Frequent coauthors

• R. W. Clayton

  33 shared

• Joann M. Stock

  26 shared

• Eric C. Ferré

  22 shared

• Guido Ventura

  Istituto Nazionale di Geofisica e Vulcanologia

  19 shared

• F. Di Luccio

  Istituto Nazionale di Geofisica e Vulcanologia

  19 shared

• Fabrício Ferreira

  18 shared

• Stephen Bowden

  Kobe University

  18 shared

• Deniz Cukur

  18 shared