H. Justus Rozemond is the recipient of the 2015 Virgil Kauffman Gold Medal Award for his development of the slip-sweep procedure that allows increased data-recording productivity with vibroseis sources. His slip-sweep concept demonstrated that high-quality vibroseis data can be acquired from several vibrator stations in a reduced time span and formed the conceptual foundation on which advances in increased data-production rates with vibroseis sources are still being made.
Biography Citation for the SEG Virgil Kauffman Gold Medal 2015
This year, the Virgil Kauffman Gold Medal is awarded to a musician who, while lost in geophysics, transposed the perpetual canon, a classical compositional technique, for seismic vibrators. This award-winning canon, named “Slip Sweep,” is much acclaimed today. But its harmony cannot compete with that which can be achieved by a string quartet or a clarinet-saxophone-marimba trio, and it was not long before the musician went back to real music. This is where he belongs and where he thrives today. 
Justus Rozemond started to study piano at age five and violin four years later. But music alone was not enough to satisfy his insatiable appetite for action. He was a very spirited and passionate young boy, keen to face all kinds of challenges, and he dedicated much time to sports and games. His parents were therefore very surprised when he finished his high-school mathematics three years ahead of his classmates. Perhaps the desire to join the very selective Dutch Student Orchestra was part of the reason for this quickness.
After obtaining a master’s degree in geophysics from the University of Utrecht, Justus studied for two years at the ENSPM in France before joining Shell in 1990. His first assignment was a research project in seismic acquisition. He participated in the design of the Shell 3D microspread experiment which opened the way to wide-azimuth land acquisition that has become today’s standard.
Justus then moved to Petroleum Development Oman (PDO). During the two Muslim holidays Eid al-Fitr and Eid al-Adha, when the Muslim nationals stay home to celebrate, PDO designs field tests that non-Muslim crew members are asked to record using the receiver spread left on site. The “delayed-sweep method” was first introduced in such a test. It consisted of two identical “voices” played by two vibrator groups with a few seconds’ delay between them.
Although seismic vibrators can play relatively sophisticated partitions, geophysicists usually restrict them to play sweeps which are essentially sinusoids with continuously variable frequency, like the glissando on a violin. However, because of the complexity of the vibrator instrument, playing this simple partition required as much patience and talent as playing the most virtuoso violin or clarinet concerto.
The test was successfully recorded, just over a huge salt dome with no internal reflectivity. If all it could demonstrate was that the method might work, it also suggested that it had the potential for a significant improvement in productivity without compromising quality.
Justus firmly believed in the method but knew that to launch it, he needed help from the rest of the geophysical community. He renamed the “delayed-sweep method” the “slip-sweep method,” and instead of filing for a patent, he presented a paper at the 1996 SEG conference in Denver. This proved to be an excellent strategy. Dedicated software was developed by a major equipment manufacturer, enabling the first slip-sweep crew to operate in 1998. A few years later, most contractors had developed their own harmonic distortion-reduction algorithms, making Justus’ vision of a large number of vibrator groups with continuous data flow (the voices in the perpetual canon) a reality.
Justus’ stay in Oman came to an end in 1997. After a few more assignments in marine acquisition and interpretation, he left Shell and geophysics in 2005. An independent and creative mind, willing to challenge conceived ideas (and authorities), Justus works today as an orchestra conductor and performer, playing mainly bass clarinet and viola in New Zealand. There, from time to time, he is reminded of his ancient seismic interest by the major fault on which he established his home.
- SOUNZ Centre for New Zealand Music: Performer
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