Spahr C. Webb

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.  His group runs a fleet of ocean bottom seismometers that have been extensively deployed for studies of the oceanic crust and upper mantle.

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 will be 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.