About

Alan Levander is the Carey Croneis Professor of Geology and Geophysics at Rice University, specializing in seismology, geophysics, structural seismology, seismic imaging, and forward modeling. His research areas focus on understanding Earth's subsurface through advanced geophysical techniques. He holds a B.S. in Geology from the University of South Carolina, an M.S. in Geophysics from Stanford University, and a Ph.D. in Geophysics also from Stanford University. Throughout his career, Dr. Levander has received numerous honors, including the Humboldt Research Prize from the Humboldt Foundation in 2006-2007 and 2012-2013, the George P. Woollard Award from the Geological Society of America in 2007, and he is a Fellow of both the American Geophysical Union and the Geological Society of America.

Research topics

• Geology
• Geophysics
• Seismology
• Artificial Intelligence
• Computer Science
• Telecommunications
• Physics
• Astrobiology
• Petrology
• Remote sensing
• Acoustics

Selected publications

• Replication Data for: Autocorrelation Seismic Imaging of Northern Taiwan Using Ambient Noise Data

  Harvard Dataverse · 2026-01-21 · 1 citations

  datasetOpen access

  This dataset contains processed vertical-component ambient-noise autocorrelation functions (ACFs) and 1-D station velocity models used for seismic imaging of crustal reflectors beneath northern Taiwan. Stations are from the Formosa Array and the Broadband Array in Taiwan for Seismology (BATS). ACF.zip provides one MATLAB file per station (acf_station.mat) containing the stacked ACF time series (acf), sampling interval (dt), lag-time vector (t), station name (station), and station coordinates (latitude/longitude/elevation). VEL_MODELS.zip provides one MATLAB file per station (vel_station.mat) containing the station name (station), depth grid (zgrid), and the velocity profiles used for depth conversion (Vp_avg and Vp_final). PICKS.xlsx contains the reflector pick times used in the manuscript (Moho, Reflector 1, and Reflector2) organized by station, along with station metadata fields as needed. These products are intended to reproduce the figures and analyses in the associated manuscript and to support reuse of the processed ACFs, velocity models, and picks for follow-on studies.

  PublisherDOI

• 3D Shear Velocity Structure of the Caribbean—Northwestern South America Subduction Zone From Ambient Noise and Ballistic Rayleigh Wave Tomography

  Geochemistry Geophysics Geosystems · 2024-09-01 · 3 citations

  articleOpen access

  Abstract The Caribbean‐South America subduction zone is a flat subduction zone, with Laramide‐style thick‐skinned uplifts occurring in the Merida Andes, Sierra de Perija Range, and Santa Marta Massif. Geodetic measurements and historical seismicity show this region is storing strain energy and is capable of a mega‐thrust earthquake ( M ≥ 8.0). Previous seismic investigations of the lithosphere and upper mantle in this area are either very large scale, very local, or only peripheral to this area; therefore, details of the Caribbean plate subduction geometry beneath the Maracaibo block remain unclear. In this study, we used a new data set acquired by the Caribbean‐Merida Andes seismic experiment (CARMA), which comprised 65 temporary broadband stations and 44 permanent stations from the Colombian and Venezuelan national seismic networks. We jointly inverted ambient noise Rayleigh wave Z / H ratios, phase velocities in the 8–30 s band and ballistic Rayleigh wave phase velocities in 30–80 s band to construct a 3‐D S‐wave velocity model in the area between 75°–65°W and 5°–12°N. The 3‐D model reveals a general increase in crust thickness from the trench to the southeast. An anomalous area is the Lake Maracaibo, which is underlaid by the thinnest crystalline crust in the region. This observation may indicate that the Maracaibo block is experiencing a contortion deformation within the crust. We also identified a high velocity anomaly above the subducting Caribbean slab, likely representing a detached piece of eclogitized Caribbean large igneous province from the base of the Maracaibo block. Additionally, our V s model clearly indicates a slab tear within the subducted Caribbean slab, approximately beneath the Oca‐Ancon Fault.

  PublisherOA PDFDOI

• Validation of <i>Ps‐P</i> Tomography for Obtaining 3D Crustal <i>V</i>_<i>P</i><i>/V</i>_<i>S</i> With Small‐<i>N</i> Data Sets: An Application to the Mount St. Helens Magmatic System

  Journal of Geophysical Research Solid Earth · 2024-09-01

  articleOpen access

  Abstract The high sensitivity of V P /V S to the presence of melt makes images of V P /V S structure particularly useful in magmatic systems, but detailed three‐dimensional models of V P /V S structure in magmatic systems are often restricted to the upper crust where there is a concentration of seismic sources used for imaging. Ps‐P tomography is a new technique that has been used to image three‐dimensional crustal‐scale variations in V P /V S in regions with limited seismic instrumentation. We apply the Ps‐P tomography technique to a well‐constrained, independently imaged magmatic setting, Mount St. Helens, to outline the efficacy and limitations of this imaging approach. Our Ps‐P tomography model reveals previously imaged high V P /V S upper crustal magma reservoirs beneath active volcanic systems at Mount St. Helens, Mount Adams and the Indian Heaven Volcanic Field and low V P /V S anomalies associated with crystallized plutons. Our model also provides new V P /V S constraints in the lower crust that reveal a high V P /V S anomaly connecting the Mount St. Helens and Mount Adams reservoirs and a low V P /V S anomaly associated with lower crustal cumulates or mafic accreted terranes. Decimation tests further show that first order V P /V S structure is recoverable using as few as four recording seismometers. These images resemble those of independent, higher resolution images from traditional techniques, highlighting the utility of Ps‐P tomography for imaging three‐dimensional variations of V P /V S throughout the crust, including in data‐poor settings or with arrays not designed for structural seismic investigations, such as many volcano monitoring networks.

  PublisherOA PDFDOI

• Seismic Autocorrelation Analysis of Deep Mars

  Geophysical Research Letters · 2023-12-13 · 5 citations

  articleOpen accessSenior author

  Abstract The InSight mission deployed one seismic station on Mars, providing a chance to apply single‐station‐based autocorrelation analysis to investigate Martian subsurface structures. However, recent analysis indicated the low‐frequency autocorrelation signals may originate from quasi‐periodic high‐amplitude instrumental “glitches” rather than the reflection response of deep Mars. In this study, we detected and removed these high‐amplitude glitches in raw seismic data and employed autocorrelation on the clean vertical component waveforms filtered between 0.05 and 0.1 Hz. We observed signals at the expected times for the olivine‐wadsleyite transition and core‐mantle boundary (CMB) as estimated by other methods. This result suggests that the low‐frequency autocorrelation signals are the reflection response from the olivine‐wadsleyite transition in the mantle and the Martian CMB region, rather than a noise phenomena. A grid search method to fit the observed PcP waveform was used to identify a layer intermediate in velocity between the Martian mantle and core at the Martian CMB.

  PublisherOA PDFDOI

• The rise of the academic science humble brag

  Zenodo (CERN European Organization for Nuclear Research) · 2023-02-26

  articleOpen accessSenior author

  One of the lesser admitted realities of academia is the need to promote one’s successes in order to curate a reputation to increase the chances of funding, promotion, and publication. This has led to the unfortunate emergence of well-intentioned self-publicizing academics.

  PublisherDOI

• Autocorrelation R₂ on Mars

  Geophysical Research Letters · 2022-09-07 · 8 citations

  articleOpen accessSenior author

  Abstract A purpose of the Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport (InSight) mission is to reveal the Martian interior structure with seismic data. In this work, ambient noise autocorrelation of the continuously recorded vertical‐component seismic signals has extracted the Rayleigh waves that propagate around Mars for one cycle, R 2 . The Mars orbiting surface waves are observed at a lag time of ∼6,000 s in the stacked autocorrelation series filtered between 0.005 and 0.01 Hz. Synthetic seismograms from a set of radially concentric velocity models were computed to find the best‐fitting one as the starting model for a Monte Carlo inversion. The starting model was randomly perturbed iteratively to increase the correlation coefficients and reduce the absolute time shifts between the synthetic and observed R 2 . An S‐wave low‐velocity layer in the inverted velocity model extends to ∼400 km depth, consistent with Marsquake observations, geophysical inversion, and high‐pressure experiments.

  PublisherDOI

• Variable Daily Autocorrelation Functions of High-Frequency Seismic Data on Mars

  Seismological Research Letters · 2022-12-29 · 11 citations

  articleOpen access

  Abstract High-frequency seismic data on Mars are dominated by wind-generated lander vibrations, which are radiated partially to the subsurface. Autocorrelation functions (ACFs) of seismic data on Mars filtered between 1 and 5 Hz show clear phases at ∼1.3, ∼2.6, and ∼3.9 s. Daily temporal changes of their arrival times (dt/t) correlate well with the daily changes of ground temperature, with ∼5% daily variation and ∼50 min apparent phase delay. The following two mechanisms could explain the observations: (1) the interference of two predominant spectral peaks at ∼3.3 and ∼4.1 Hz, assumed to be both lander resonance modes, generate the apparent arrivals in the ACFs; (2) the interference of the lander vibration and its reflection from an interface ∼200 m below the lander generate the 3.3 Hz spectral peak and ∼1.3 s arrival in the ACFs. The driving mechanism of the resolved dt/t that most likely explains the ∼50 min delay is thermoelastic strain at a near-surface layer, affecting the lander–ground coupling and subsurface structures. The two outlined mechanisms suggest, respectively, up to ∼10% changes in ground stiffness at 1–5 Hz and ∼15% velocity changes in the top ∼20 m layer. These are upper bound values considering also other possible contributions. The presented methodology and results contribute to analysis of ACFs with limited data and the understanding of subsurface materials on Mars.

  PublisherOA PDFDOI

• Seismic evidence for lithospheric boudinage and its implications for continental rifting

  Geology · 2022-05-12 · 1 citations

  article

  Abstract The continental rifting that precedes the breakup of a continent and the formation of a new ocean basin is one of the key processes of plate tectonics. Although often viewed as a two-dimensional process, rifted margins exhibit significant variations along strike. We document along-strike variations developed during the ca. 200–160 Ma continental rifting that formed the margins of the Gulf of Mexico ocean basin. Rayleigh-wave ambient noise tomography reveals a zone of high and low seismic velocity resembling large scale geologic boudins in the mantle lithosphere of the northwestern Gulf of Mexico margin. These features become progressively less prominent eastward following the transition from a magma-poor to a magma-rich passive margin. We infer that mantle refertilization and thickness of the pre-rift lithosphere control deformation style and the along-strike variations in continental rifting. Our results also suggest that deformation during rifting produces long-lived features that persist long after breakup and, therefore, can be used to study rifted margins globally.

  PublisherDOI

• Insights on Formation of the Gulf of Mexico by Rayleigh Surface Wave Imaging

  Geochemistry Geophysics Geosystems · 2022-11-29 · 3 citations

  articleOpen access

  Abstract We used cross‐correlation of ambient noise records from seismic stations in the US, Mexico, and Cuba to extract dispersion data of Rayleigh surface wave. Our derived 3D shear‐wave velocity model of the greater Gulf of Mexico (GOM) region captures variations in the crustal and lithospheric structures across the continental margins of the US Gulf Coast and Yucatan, Mexico. The model shows a zone of reduced velocity in the mantle lithosphere underlying the extended continental margin of the northwestern GOM. We attributed this velocity reduction to extensional deformation and melt‐induced weakening of the lithosphere during the Triassic continental rifting that preceded the seafloor spreading that formed the GOM. Melt extraction might have been hindered by the greater lithospheric thickness in the western region along the US Gulf Coast margin that resulted in the westward decrease of rift‐related volcanism/magmatism reported from previous studies. The clear asymmetry between the US Gulf Coast and its conjugate Yucatan margin suggests extension along a shear‐zone that focused more deformation on the North American plate prior to breakup. In contrast to the counterclockwise rotation of the Yucatan block during seafloor‐spreading, our analyses using deformable plate models demonstrate that continental rifting occurred in a predominantly northwest‐southeast direction. This change in plate motion is attributed to the development of mantle shear‐zones in the western part of the rift. We estimated the depth of the lithosphere‐asthenosphere boundary and determined that the extended continental and oceanic lithospheres have mostly regained their thickness since the time of breakup.

  PublisherDOI

• AUTOCORRELATION REFLECTIVITY IMAGING INSIDE THE UPPER MAGMA STORAGE ZONE OF THEMOUNT ST HELENS TRANSCRUSTAL MAGMA SYSTEM

  Abstracts with programs - Geological Society of America · 2022-01-01

  article1st authorCorresponding
  PublisherDOI

Recent grants

• Collaborative Research: Making the San Andreas Fault at the Mendocino Triple Junction

  NSF · $74k · 2007–2010

• Investigating Flat Slab Subduction and Plate Edge Tectonics in Northern South America

  NSF · $600k · 2015–2019

• CMG: Adjoint, Migration, and Velocity Analysis Methods for Imaging the Earth's Upper Mantle: Theory and Application

  NSF · $500k · 2006–2012

• Collaborative Research: Crust-Mantle Interactions at an Oblique Arc-Continent Collision Zone: The SE Caribbean Plate Boundary

  NSF · $319k · 2006–2011

• Collaborative Research: The Cenozoic history of the western US - a data integration strategy for Earthscope

  NSF · $59k · 2004–2008

Frequent coauthors

• C. A. Zelt

  80 shared

• Fenglin Niu

  Rice University

  48 shared

• I. Palomeras

  37 shared

• R. Carbonell

  Geociencias Barcelona

  34 shared

• Brandon Schmandt

  University of New Mexico

  32 shared

• E. Kiser

  University of Arizona

  32 shared

• Maximiliano Bezada

  University of Minnesota System

  29 shared

• M. B. Magnani

  Southern Methodist University

  28 shared

Awards & honors

• Humboldt Research Prize, Av Humboldt Foundation, 2012-2013
• Humboldt Research Prize, Av Humboldt Foundation, 2006-2007
• George P. Woollard Award, 2007, Geological Society of Americ…
• Fellow, American Geophysical Union, 2001
• Fellow, Geological Society of America, 1997