Oscillations planétaires evokes geology.
In all the layers that make it, from its core to its surface areas, Planet Earth is inhabited by undulatory motions of extremely varied temporal scales. Some are inscribed in a geological timeframe while others follow a daily cycle. This oscillatory ensemble contributes to the mechanisms that rule the Earth’s dynamics.
These are the phenomena evoked in the work.
Every year, there are between 800,000 and 1,000,000 earthquakes worldwide. Most of these tremors are too weak to be felt or happen in uninhabited areas.
- Antarctic Plate
Tectonic plates move in relation to one another. The Antarctic Plate moves slowly at a speed of a few millimetres to two centimetres per year, depending on its contact zones with the dozen or so plates and microplates hooked to its perimeter.
- Subduction happens when two plates collide. The densest plate dives under the other one, sinking into an extremely hot layer of the Earth called the mantle, dragging along water and the sediments that accrued on it over millions of years.
- Oceanic Trench
Challenger Deep is the deepest point known on Earth. It hides at the bottom of the Mariana Trench, at a depth of close to 11 kilometres under the surface of the Western Pacific Ocean, near the Mariana Islands.
- Mantle Convection
Plate tectonics revolutionized Earth sciences when it was formulated as a theory in the 1960s, giving birth to several hypotheses about the mechanics that set plates in motion. Today, we know that the key of this mystery resides in the convection of the Earth’s depths.
- Geysers are naturally occurring phenomena that are extremely frail and sensitive to earthquakes. Their activities vary according to the impact earthquakes have on their structure.
- Mountain Building
Mountain ranges are mostly formed in subduction zones. When a continental plate encounters an oceanic plate, the latter, denser, slides under the former, which, now under tremendous pressure, ridges and rises.
- Earth Tide
In 1994, Maya Tolstoy, a renowned marine geophysicist and scientist, discovered the first concrete evidence that tides – the movements of oceans and solid earth in response to astronomical forces – can trigger underwater earthquakes. “On sea floors, where the weight of the ocean exerts downward and upward pressures, the floor moves with the water in relation to this distortion,” she tells. “It is as if the seabed was breathing along with the tides.”
The magnetic field of the Earth has a strange ability: it can flip, meaning that the North Pole becomes the South Pole and vice versa. Magnetic inversions happen periodically, but at irregular, unpredictable intervals. The Earth has known hundreds of such inversions in its lifetime. The last one happened about 780,000 years ago.
- Mid-Atlantic Ridge
The Mid-Atlantic Ridge is part of a wide network of underwater volcanic mountain ranges. It runs for 10,000 kilometres through the Atlantic Ocean. And despite an average height of 3,000 metres, it emerges at only nine spots where it forms volcanic islands and rocky peaks.
- Seismic Waves
When an earthquake is triggered, a front of seismic waves propagates through geological layers to reach the surface of the Earth. These waves are very fast and elastic; they run in all directions from their point of origin.
[English translation: François Couture, x-19]
Oscillations planétaires [Planetary Oscillations] was realized in 2017-18 at the composer’s studio in Montréal and premiered on July 13, 2018 on the radio program Klangkunst broadcast by Deutschlandfunk Kultur (Germany). A preliminary version of two movements premiered on August 13, 2017 under the title Nazca Plate, Sound Essay on Geological Time during the concert Time Response programmed by Sound Travels, a festival presented by NAISA at Ernest Balmer Studio in Toronto (Canada). Oscillations planétaires received its concert premiere on December 6, 2018 during the concert Électrochoc 3 presented in the Studio multimédia of the Conservatoire de musique de Montréal (Québec). The work was revised in August 2019. With the participation of: Ida Toninato, baritone saxophone (Convection mantellique and Marée crustale); Claire Marchand, flute (Geysers); Daniel Áñez, piano (Dorsale médio-atlantique); Christian Olsen, drum kit (Dorsale médio-atlantique and Ondes sismiques). Thank you to Fiona Ann Darbyshire (scientific advisor, Département des sciences de la Terre et de l’atmosphère, UQAM), Marcus Gammel (who originated the commission) and the Canada Council for the Arts (CCA). Oscillations planétaires was commissioned by Deutschlandfunk Kultur (Germany).
July 13, 2018, Radio premiere: Klangkunst, Deutschlandradio Kultur, Germany
December 6, 2018, Concert premiere: Électrochoc 2018-19: Électrochoc 3: Chantal Dumas — Oscillations planétaires, Studio multimédia — Conservatoire de musique de Montréal, Montréal (Québec)