Jack Oliver (1923-2011) Seismologist Who Helped Demonstrate That Earth’S Continents Move Constantly

COMMENt Obituary Jack Oliver (1923-2011) Seismologist who helped demonstrate that Earth’s continents move constantly.

ohn “Jack” Ertle Oliver, who died on raise the game of seismology in the hope of not occur where temperatures were too great 5 January aged 87, was one of the found- finding ways to detect and identify under- to support the needed stresses, but instead Jing fathers of modern seismology, plate ground nuclear explosions. (The Limited Test happened within slabs of still-cold lithosphere tectonics and deep imaging of Earth’s conti- Ban Treaty, which banned nuclear tests from that had plunged rapidly to great depth. nental crust. He and Bryan Isacks, a former the atmosphere, underwater and in space, but Like many founders of plate-tectonics graduate student whom he had advised, not from underground, was ratified in 1963.) theory, Oliver soon changed direction. In showed that not just Earth’s crust, but the Modern seismology grew rapidly out of the 1971, he left Columbia University to revive entire 100-kilometre-thick outer layer of panel’s recommendation to build a global the geological-sciences department at Cor- Earth, the lithosphere, moves over the face suite of detector stations — the World-Wide nell University in Ithaca, New York, and of the planet before plunging into the weaker Standardized Seismograph Network. turned his attention to one of the blind spots underlying asthenosphere. This discovery Following Ewing’s philosophy again, in Earth science, the lower crust. He launched gave the then-controversial theory of con- Oliver and Isacks installed seismographs the Consortium for Continental Reflection tinental drift a solid foundation, paving the in Fiji and Tonga to study what were then Profiling, which pioneered the use of seismic way for plate tectonics. reflection technology — developed Two strong personalities had key in the oil industry — to explore the roles in Oliver’s scientific develop- lower crust of continents. It has since ment. The first was Paul Brown, been copied by numerous nations. his high-school American-football He always worked to instil a sense coach in Massillon, Ohio — who of teamwork, and tried to erase the later found fame as coach of the differences between geologists (some- Cleveland Browns and founder times belittled for being quantitatively of the Cincinnati Bengals. Brown challenged) and geophysicists (some- was famously intolerant of prima times perceived as believing only donnas, and Oliver’s philosophy of what they could not see with their science and administration followed eyes). Cornell led the widespread the same principle — that good transformation of geology and geo- scientists who worked together could physics departments into integrated produce more important science than Earth-science departments. the best scientists working alone. Oliver continually inspired stu- Supported by a football scholarship, dents around him, asking, almost as Oliver studied physics at Columbia an interogative mantra: “What is the University in New York, interrupted by three one of Earth’s enigmas: deep earthquakes. next most important problem?” He once said, years of service in the Navy from 1943 to These occur at 300–700 kilometres below “Sure. I want to work with bright students, 1946. On returning he met Maurice Ewing, the surface, where pressures and tempera- but what I really want are students who can who became his PhD adviser. Ewing instilled tures seemed far too high to allow rock to ask good questions.” Time and again he dem- in Oliver the view that going where no one fracture. With seemingly little more than a onstrated that asking the right question was had gone before offered a high probability glance at their seismograms, they knew they a shortcut to answering an important one. of scientific discovery, and that discovery had something important: P and S waves Spicing his later writings with limericks, he was fun — jet fuel to a man with insatiable with unusually high frequencies. They real- once wrote: curiosity. ized that the lithosphere (which includes the In the 1950s, most seismologists recorded planet’s crust and the uppermost ‘cool’ part “If creativity is what you strive for, Earth’s tremors by measuring the arrival of the mantle) underlying the Pacific Ocean The status quo you must learn to abhor, times of two types of seismic wave, P and S to the east had plunged to a depth of 700 kil- Chains of convention unfetter, waves, at their seismographs. These waves ometres. Much of the scientific community Seek the different yet better, travel through the interior of Earth. Long- was slow to appreciate their insight, for few Pay no attention to those keeping score!” period waves that ripple over the surface of seismologists had turned their attention to the planet offered a ‘place’ where few had the theory of continental drift, or even taken Not a self-promoter, Oliver was as at home gone before. Oliver was the first to recognize it seriously, but scepticism quickly gave way with technicians as with academicians. He many of the peculiarities of the waveforms to consensus with another of their studies. died while in lucid conversation with his that computers now analyse and simulate. In 1968, with Lynn Sykes, another long-time administrative assistant, Judy His papers from this period show exquisite researcher who had been advised by Oliver, Healey, abruptly announcing, without con- recordings of surface waves, buttressed by Oliver and Isacks published what must be the cern: “I’m done.” ■ sensible interpretation. most widely read seismological paper ever Towards the end of that decade, Oliver written, ‘Seismology and the new global tec- Peter Molnar is at the Department of joined about a dozen of the country’s out- tonics’ in the Journal of Geophysical Research. Geological Sciences at the University of standing scientists to form the Berkner Panel Among their many insights, they realized that Colorado in Boulder, Colorado 80309, USA. on Seismic Improvement. This was meant to the formerly enigmatic deep earthquakes did e-mail: [email protected]