Dr. Spahr C. Webb

Jerome M. Paros/Lamont Senior Research Professor, Seismology, Geology and Tectonophysics, Lamont-Doherty Earth Observatory (LDEO), Columbia Climate School

Adjunct Professor, Department of Earth and Environmental Sciences (DEES), Lamont-Doherty Earth Observatory (LDEO)

Room 107, Seismology Bldg
61 Route 9W
PO Box 1000
Palisades, NY 10964


Spahr Webb holds the Jerome M. Paros/Lamont Research professorship in Observational Sciences at the Lamont Doherty Earth Observatory which Is part of Columbia University’s new Climate School. He is also an Adjunct Professor within the Department of Earth and Environmental Sciences Department of the Columbia University.  His group develops instrumentation to better observe geophysical and oceanographic processes. A principle focus now is on subduction zones and the hazards of megathrust earthquakes with an emphasis on observing slow slip events (SSEs or slow earthquakes). The distribution of slip in SSEs  should inform on the coupling behavior of megathrust faults and which have preceded several recent giant earthquakes, and thus may provide the potential for early warning. Other efforts include measuring deformation near the trench of subduction zones using GPS-acoustic techniques, monitoring magma chamber processes beneath Axial volcano using the compliance method. 

Current projects include a two year project starting Oct. 2022 using absolute pressure gauges combined with oceanographic observations and on shore and offshore geodetic observations to observe slow slip events (earthquakes) offshore of New Zealand. 

A group of three GPS-A (GPS acoustic) geodetic sites were established offshore the Aleutian subduction zone in 2018 in the Shumagin seismic gap region about 70km from the trench. The sites were used to measure interseismic strain accumulation and then also the seafloor displacements caused by the huge 2021 Sand Point and Simenof and 2022 Chignik earthquakes that occured beneath the array. 

Three instruments were temporarily deployed to measure seafloor compliance to investigate the magma chamber beneath Axial Volcano in June 2022. 

Spahr Webb hold B.S. degrees in Physics and also Earth and Planetary Sciences from MIT and a PhD in oceanography from the Scripps Institution of Oceanography.


Only select projects listed below
Name Start Date End Date
Exploring the absolute pressure gauge data from the Cascadia Initiative OBS deployment for transient changes in seafloor elevation 4/15/15 3/31/17
Alaska Amphibious Community Seismic Experiment 8/15/17 7/31/20
Collaborative Research: Along Strike Variation in Shallow, Offshore Strain Accumulation and Slow Slip at Hikurangi Subduction Margin, New Zealand 4/1/18 3/31/22
Collaborative Research: Crustal Accretion and Mantle Processes Along the Subduction-Influenced Eastern Lau Spreading Center 9/1/08 8/31/14
Collaborative Research: Measuring Strain along the Aleutian Subduction Zone Trench to better constrain seismic and tsunami hazard 9/1/17 8/31/20
Establishing a Long-Term Geodetic Network at the East Pacific Rise Ridge 2000 Integrated Studies Site 4/1/07 9/30/13
LDEO/OBS Laboratory Participation in GNS Hikurangi Experiment 7/1/18 6/30/21
Megathrust Seismic Hazard by Reflection Mapping 1/1/10 3/31/14
Three Compliance Instruments for Axial Volcano to Observe Long Term Evolution of the Magma Chamber and in Support of OOI Observations 10/1/19 9/30/21
Validating Pressure Gauges for Seafloor Seismology and Geodesy 12/1/19 11/30/21
Worthington Deployment 4/1/20 7/31/23
Southern Pacific Cruise 10/1/20 9/30/21
Collaborative Research: Vertical Seafloor Geodesy to Accurately Image Slow Slip Events in a NoisyOcean Environment 2/1/22 1/31/23
Collaborative Research: Near-Trench Community Geodetic Experiment 1/1/23 12/31/27
OBSIC: Hooft Galapagos Cruise 2/1/23 7/31/23
NCDP - Thought Leadership Strategy for ComEd 1/4/21 12/31/21