The Earth Gravity Site on Mount Newton, in John Dean Provincial Park – was created in 1979. It’s one of 5,737 control stations that were systematically established across Canada in the 1970s. Ours is located inside the park, on the west side of Dean Park Road, 30′ NE of the upper over-flow parking lot, in a mossy meadow.
The Centre for Remote Sensing Geodetic Survey Division, located at the Institute of Ocean Sciences in Pat Bay – set a round brass plug into the bedrock. Written on the plug is National Gravity Net. Next to the plug are three additional blank brass plugs, forming a triangle. The purpose of making repeated and very accurate geodetic surveys is partly related to earthquake studies; and provides fundamental information for mapping, charting, navigation, boundary demarcation and crustal deformation.
All the information collected from the Canadian Gravity Standardization Net (CGSN), is based on the International Gravity Standardization Net (IGSN71). The data is considered accurate to tens of microgals, and is stored within the Canadian Gravity Database located in Ottawa, and is available to the international geoscience community. The database contains information from more than 400 projects, approx. 10,000 gravity control stations – 118,000 gravity network ties.
Primarily, this site permits field testing of gravimeters. These precise gravity surveys have been carried out on the west coast since 1977. Scientist through the use of these instruments, are seeking to monitor very subtle changes in: elevations, the density of the underlying rock, and the redistribution of subsurface mass brought about by the formation of cracks or the flow of water.
If you have a chance, I’d highly encourage you to also visit the sister site, within Gulf View Park, located at the base of Dean Park Road. Follow the new trail; below the hump of bedrock and above the old parking lot, look for the 1939 cement gazebo foundation. After a moment you’ll see the brass plug on top – and you’ll be surprised when your eye catches it – a highlight find…