Gravimeters (or gravity meters) measure the gravity field of the Earth with such a resolution that they can detect very small changes in the underlying or surrounding structures. Their resolution is in the order of 0.01 micro-Gal in a gravity field of 980,000,000 micro-Gal. This resolution enables them to detect minute changes due to fluid motion in the seafloor or magma movements in or below the earth crust, dependent where they are located. The gravimeter of Ocean Networks Canada is placed in gimbals which are carefully balanced so that it will naturally swing into a level position when deployed. The gravimeter is part of a Seafloor Compliance (SFC) apparatus together with a Differential Pressure Gauge (DPG), designed and built by the University of Toronto. The seafloor compliance method can monitor changes in the stiffness of a gas hydrate zone or a magma chamber. The seafloor responds subtly to pressure variations caused by waves. The induced pressure from the waves at the sea surface is detected by the DPG, and the motion of the seafloor, which is dependent on its stiffness, is detected by the high-precision gravimeter.
Individual instruments of the above category, which are (or have been) connected to our observatories. Click an instrument for detailed information.
|Seafloor Compliance (SFC)||Marine Technology Centre|
Click the instrument categories below for descriptions and lists of instruments belonging to that category.