Earthquakes, Magnetism and Tides

Contained within the 3rd Edition (1957) of the Atlas of Canada is a plate that shows maps of earthquakes, magnetism and tides across Canada. The two larger upper maps on this plate show geomagnetism. Since the North Magnetic Pole is in a different position from the Geographical North Pole, and the lines of the earths magnetic forces are deflected by various agencies, the compass needle does not point toward the Geographical North Pole in most locations. The deflection of the compass needle from True North is called magnetic variation or declination. Thus, for example, where variation is west, north as indicated by the compass needle is west of True North by the number of degrees marked on the isogones, as illustrated by the upper left map on this plate. The upper right map indicates the average annual change of magnetic variation in minutes. The small inset map at the top of this plate, entitled Earthquake Probability, shows the damage which may result from earthquakes occurring in different parts of the country. The zones are graded from 0, where such earthquakes are likely to do no damage, to 3, where earthquakes are likely to do major damage. The small-type numbers indicate…

Publisher

Natural Resources Canada

Resources

4

Catalogue metadata updated

2022-03-14