An InterRidge cruise bursary is available for an early-career scientist, to allow participation on the HYDROBS-MOMAR2 cruise in July-August 2012, the Chief Scientist being Julie Perrot. Details of the bursary and an application form can be found at: http://www.interridge.org/cruisebursary and should be sent to the InterRidge Offce (coordinator@interridge.org)
Cruise objectives
The main objective of the HYDROBS-MOMAR2 cruise is to increase the length of the hydroacoustic data series of observation over the MOMAR area using five hydrophones moored in the SOFAR channel. The cruise leaves Las Palmas, Canary Islands, Spain, on 29th July and arrives at Ponta Delgada, Azores, Portugal on 11th August 2012.
Applicant details
The scientific objectives of the candidate is to both: 1) learn how to deploy hydrophones and become familiarized with oceanographic surveys and 2) understand the methodology by programming the parameters of the hydrophones. This is a good opportunity for a future marine geophysicist or marine mammals biologist (we also record the sound of whales, among others).
Background
The detection and localization of numerous low-magnitude earthquakes occuring along active oceanic ridges provide important insights into the various magmatic, tectonic or hydrothermal processes that generate these earthquakes. However, these processes mainly generate low-magnitude seismic events that are not detected by land-based seismological global networks. The deployment of autonomous hydrophone arrays, moored within the SOFAR channel, a wave-guide in which acoustic waves propagate over long distances with little attenuation, overcomes this difficulty. Hydrophone arrays have shown their capability to detect and precisely locate (< 2 km) typically 30 to 40 times more events than those listed in global catalogues.
The interpretation of acoustic data recorded by two large hydrophone arrays deployed north of the Azores (the SIRENA array) and south of 35°N (the ''South Azores'' array) has evidenced the low seismicity rate of most of the section of the Mid-Atlantic Ridge which encompasses the MOMAR area: only very few seismic swarms were observed, separated by long periods of quiescence. Acoustic data recorded by the first array dedicated to the monitoring of the MOMAR area shows an important magmatic activity where only tectonic swarms are observed.
