Instrumentation engineer – Ocean Bottom Seismometers - OBS
250 rue Albert Einstein, bât 1
06560 Valbonne, France
Tel: +33 (0)4 83 61 87 86
Responsabilities and functions at geoazur
In 2014 I assumed the responsibility of the Geoazur OBS pool and its technical group of engineers. This is part of the pôle « Fonds Marin » of Géoazur, headed by Dr. Audrey Galve.
I am directly involved in and oversee all technical aspects and developments of our OBS pool, as well as interfacing with researchers for organizing campaigns using the OBS and also working together with Audrey Galve to better integrate the Geoazur OBS pool into the french and european OBS community.
career evolution with obs
I’ve been working with Ocean Bottom Seismometers since 1995, when I began working with Dr. Yosio Nakamura at the University of Texas Institute for Geophysics on the OBS that he developed in the early 1990s. This exact same design was used to build the IRD (Orstom at the time) instruments – these are the instruments which were used by Géoazur primarily between 1993 and 2005.
During my first few years at UTIG I contributed a few technical improvements to the instruments and handled all the OBS campagne preparations. Later I began working on the new datalogger design that we currently are using at Géoazur. UTIG is now also building some new instruments using this electronics package.
I joined IRD and the OBS team at Géoazur in 2004 and during that year completed the design for the electronics system of our new generation of OBS which was called the Hippocampe (see photo above). In 2004 we built 20 instruments and a few years later 10 more. Around 2010, 20 more were built, this time with just one sphere with an integrated 4.5 Hz geophone sensor (after the UTIG model), making these OBS much better adapted to seismic refraction studies. This OBS was called the Ladybug. The 20 were never completed due to lack of funding. I have just recently managed to find funding to complete these instruments, giving Géoazur a total of over 40 functional OBS (several have been lost over the years of use).
RECENT AND NEW DEVELOPMENTS
There are a few major developments in progress in the Géoazur OBS pool.
In the past for passive seismology campaigns we used 4.5 Hz geophones and Guralp 40T sensors. We are now gradually moving to using 2 Hz geophone sensors along with Trillium compact 120 second sensors. We now have one Trillium compact and will finish building seven to nine 2Hz sensors this year. These 2 Hz sensors will have the reliability and low power consumption of geophone sensors while providing an excellent tool for local and micro-seismicity studies. This should fill an important niche in the european OBS landscape.
The second change is that we will no longer have the two versions of OBS – Hippocampe with 2 spheres and Ladybug with one sphere. Very soon, all of our 40-plus OBS will have the 4.5 Hz integrated geophone packages, and thus will be compact and easy to use and deploy, and thus perfectly adapted to OBS refraction studies. While these OBS are mainly intended for refraction studies, they can also be used for passive seismology as they are capable of 6 month long deployments.
Our OBS with 2 Hz sensors can be used with a single sphere for 6 month deployments or two spheres for year long deployments. The sensor is physically attached to the OBS and its anchor, thus giving very good mechanical coupling with the seafloor. The Trillium compact sensors require 2 spheres for a 6 month deployment due to the weight of the sensor package. We have not yet fully determined whether we can do year long deployments with the Trillium compact sensors, but believe it to be
Bachelor of Science in Electrical Engineering, 1988, University of Texas at El Paso