About

Sridhar Anandakrishnan is a professor in the Penn State Department of Geosciences with a background in geophysics, glaciology, and electrical engineering. His research group, the Penn State Ice and Climate Exploration (PSICE), is involved in projects that utilize satellite remote sensing, geophysics, modeling, and laboratory measurements of ice properties. He is part of a large project to characterize Thwaites Glacier in Antarctica to help project its future contribution to sea level rise, and collaborates on studies of the calving and flow of Helheim Glacier in Greenland. Using geophysics and drilling, his work includes mapping the history of the Greenland Ice Sheet as part of the GreenDrill project. Anandakrishnan is interested in understanding the response of the ice sheets of Antarctica and Greenland to climate change, focusing on subglacial geological and geophysical conditions such as sedimentary basins, crustal heat flow, bed-forms, roughness, and hydrology, which have significant societal impacts through sea level change. He is open to welcoming new students, including undergraduates interested in classes, senior theses, projects, and graduate students pursuing Master’s or Ph.D. degrees in glaciology.

Research topics

• Geology
• Geomorphology
• Oceanography
• Geography
• Remote sensing
• Physical geography

Selected publications

• Echoes Below: Insights from Sticky Spots near the Rutford Ice Stream Grounding Line

  2026-01-04

  article
  PublisherDOI

• A high-resolution icequake catalog from Rutford Ice Stream via an enhanced QuakeMigrate workflow with integrated GrowClust support

  Annals of Glaciology · 2026-01-01

  articleOpen access

  Abstract We present a high-resolution dataset of over one million icequakes located just upglacier of the grounding line of Rutford Ice Stream, West Antarctica, spanning a 23 day period during January 2019. The icequakes were identified and located initially using the QuakeMigrate software, and their locations can be refined using the GrowClust software. These two tools naturally complement one another: QuakeMigrate detects and locates large numbers of events, while GrowClust enhances location precision by relocating events using QuakeMigrate’s robust picks and locations. To support this workflow, we introduce QuakeSupport, a supplementary package developed to facilitate and extend the use of both tools. Based on our extensive use of QuakeMigrate and GrowClust, we identified common processing needs—automating data preparation, efficiently managing extended QuakeMigrate runs and converting QuakeMigrate outputs for GrowClust—which QuakeSupport addresses through an end-to-end workflow. By reducing the learning curve and improving processing efficiency, QuakeSupport enables researchers to focus on scientific analysis. Together with the Rutford dataset, this integrated and scalable approach demonstrates a framework for generating (cryo)seismic event catalogs in the era of increasingly larger seismic data volumes.

  PublisherOA PDFDOI

• Heterogeneous subglacial sediments beneath Thwaites Glacier, West Antarctica, inferred from seismic data

  2026-04-09 · 1 citations

  articleOpen access

  Constraining the properties of subglacial materials is key to the accurate parameterisation of glacial slip in ice sheet models and is therefore important for accurate projections of sea level rise. The bed of Thwaites Glacier, West Antarctica, is particularly important because Thwaites is key to the stability of the West Antarctic Ice Sheet. We report the results of active-source seismic surveys undertaken during the 2023/24 Antarctic field season, immediately upstream of the subglacial ridge known as Ghost ridge. These include a 14.4 km profile of normal-incidence data and wide angle data over sections totalling ∼ 5 km. Estimation of basal acoustic impedance reveals that the bed in this region is composed of sediments, with regions of dilatant sediments and regions of stiffer sediments present. Amplitude-versus-angle (AVA) analysis of wide angle data supports this interpretation, with soft bed regions displaying high Poisson’s ratios (> 0.45). We image bedforms which are interpreted as sedimentary depositional bedforms, one of which we interpret as a crag and tail formation, and the other of which appears as a sedimentary tail emerging from rolling topography upstream. The tails of these features are probably composed of dilatant till. We apply Viscous Grain Shearing (VGS) theory to results obtained from AVA analysis to constrain the porosity and effective pressure of the subglacial sediments. VGS analysis suggests that the changes in reflectivity along our seismic profile may be primarily controlled by changes in effective pressure at the ice base rather than porosity.

  PublisherDOI

• Hard rocks and deep wetlands beneath Thwaites Glacier in Antarctica

  Communications Earth & Environment · 2026-04-24

  articleOpen access

  Thwaites Glacier in West Antarctica is losing ice rapidly and is considered especially vulnerable to retreat, but predictions of its future remain limited by uncertainties about its subglacial properties. Here we show results from 344 km of vibroseismic surveys collected along and across the glacier. The data reveal a heterogeneous bed of elevated ridges with steep upstream-facing slopes that form crag-and-tail landforms resisting fast flow. Between these ridges lie basins filled with consolidated sediments. Subglacial water is widespread, occurring in bed depressions and on topographic highs, including an active lake composed of tens of metres of highly porous, water-saturated sediments. Across the glacier, the bed beneath the eastern margin is mostly hard but contains isolated pockets of softer material. These findings demonstrate current models do not capture the full complexity of the bed beneath Thwaites Glacier, where water-bearing sediments and steep basal slopes strongly affect ice flow and retreat.

  PublisherOA PDFDOI

• Deglaciation of the Prudhoe Dome in northwestern Greenland in response to Holocene warming

  Nature Geoscience · 2026-01-05

  article
  PublisherDOI

• Supplementary material to "The Antarctic Ice Sheet sliding law inferred from seismic observations"

  2025-03-17

  preprintOpen accessSenior author
  PublisherDOI

• Holocene deglaciation of Prudhoe Dome, northwest Greenland

  2025-05-15 · 1 citations

  preprintOpen access

  Projections of future sea-level rise benefit from understanding the response of past ice sheets to interglacial warmth. Constraints on the extent of inland Greenland Ice Sheet (GrIS) recession during the Middle Holocene (~8 – 4 ka) are limited because geological records of a smaller-than-modern phase largely remain beneath the modern ice sheet. We drilled through 509 m of firn and ice at Prudhoe Dome (PD), northwest Greenland to obtain sub-ice material yielding direct evidence for the response of the NW GrIS to Holocene warmth. Our infrared stimulated luminescence measurements from sub-ice sediments indicates that the ground below the summit was exposed to sunlight at 7.1 ± 1.1 ka. This complete deglaciation of PD, coeval to reduced extent at other ice caps across Northern Greenland, is further supported by interglacial-only δ18O values from the PD ice column as well as ice depth-age modeling. Our results point to a significant response of the NW GrIS to early Holocene warming, estimated to be +3–5 ℃ from paleoclimate data. This range of summer temperatures is similar to projections of warming by 2100 CE.

  PublisherOA PDFDOI

• Rift‐Related Sedimentary Basin and Deeper‐Seated Mafic Intrusions Modeled Beneath Thwaites Glacier, West Antarctica: Influence on Glacier Dynamics

  Journal of Geophysical Research Solid Earth · 2025-09-26 · 1 citations

  articleOpen access

  Abstract Thwaites Glacier in West Antarctica has been identified as a route to destabilization of the whole West Antarctic Ice Sheet, potentially leading to several meters of sea‐level rise. However, future evolution of Thwaites Glacier remains uncertain due to a lack of detailed knowledge about its basal boundary that will affect how its retreat proceeds. Here we aim to improve understanding of the basal boundary in the lower part of Thwaites Glacier by modeling the crustal structures that are related to the bed‐type distribution and therefore influence the basal slip. We combine long‐offset seismic, and gravity‐ and magnetic‐anomaly data to model the crustal structures along two 120 km lines roughly parallel to ice flow. We find a sedimentary basin 40 km in length in the along‐flow direction, with a maximum thickness of 1.7 0.2 km, and two mafic intrusions at 5–10 km depth that vary in maximum thickness between 3.8 and 8.6 km. The sedimentary basin and major mafic intrusions we modeled are likely related to the multi‐stage tectonic evolution of the West Antarctic Rift System. Thwaites Glacier flows across a tectonic boundary within our study site, indicating it flows across tectonically formed structures. The varying geology and resulting variations in bed types demonstrate the influence of tectonics on Thwaites Glacier dynamics.

  PublisherOA PDFDOI

• The Antarctic Ice Sheet sliding law inferred from seismic observations

  2025-03-17 · 1 citations

  preprintOpen accessSenior author

  Abstract. The response of the Antarctic ice sheet to climate change and its contribution to sea level under different emission scenarios are subject to large uncertainties. A key uncertainty is the slipperiness at the ice sheet base and how it is parameterized in glaciological projections. Alternative formulations of the sliding law exist, but very limited access to the ice base makes it difficult to select among them. Here, we use satellite observations of ice flow, inverse methods, and a theory of acoustic propagation in granular material to relate the effective pressure, which is a key control of basal sliding, to seismic observations recovered from Antarctica. Together with independent estimates of grain diameter and porosity from sediment cores, this enables a comparison of basal sliding laws within a Bayesian framework. The presented direct link between seismic observations and sliding law parameters can be readily applied to any acoustic impedance data collected in a glacial environment. For rapidly sliding tributaries of Pine Island Glacier, these calculations provide support for a Coulomb-type sliding law and widespread low effective pressures.

  PublisherDOI

• Geophysical surveys and instrument incubation program across a glacier grounding zone: Eastwind Glacier's contribution to McMurdo ice shelf mass balance

  2025-01-14 · 1 citations

  preprint
  PublisherDOI

Recent grants

• Collaborative Research: Integrative Study of Marine Ice Sheet Stability & Subglacial Life Habitats in W Antarctica - Lake & Ice Stream Subglacial Access Research Drilling (LISSARD)

  NSF · $391k · 2009–2014

• Characterization of Lake Amundsen-Scott, S. Pole: A Ground Geophysical Program

  NSF · $235k · 2006–2010

• Rutford Ice Stream Cooperative Research Program with British Antarctic Survey

  NSF · $142k · 2018–2022

• SST: Sensor Network for 3D Geophysical Imaging of Glaciers and Ice Sheets

  NSF · $523k · 2005–2009

• NSF-NERC: Ground Geophysics Survey of Thwaites Glacier

  NSF · $3.0M · 2018–2026

Frequent coauthors

• Richard B. Alley

  Pennsylvania State University

  218 shared

• Knut Christianson

  University of Washington

  107 shared

• Douglas A. Wiens

  Washington University in St. Louis

  107 shared

• A. Nyblade

  85 shared

• B. R. Parizek

  Pennsylvania State University

  80 shared

• Huw Horgan

  73 shared

• J. Paul Winberry

  Central Washington University

  65 shared

• R. C. Aster

  Colorado State University

  58 shared

Education

• PhD, Geology

  University of Wisconsin Madison

  1990

• MS, Electrical Engineering

  Columbia University

  1983

• BS, Electrical Engineering

  Columbia University

  1982