coseismal

adj

1. Of or pertaining to a line on a map connecting places simultaneously affected by a seismic event.

noun

1. A line on a map connecting places simultaneously affected by a seismic event.

   “As illustrative of what would occur under the supposed conditions Dr. Schmidt gives a diagram like fig. 32, in which coseismals have been drawn on the assumption that the velocity has increased proportionately with the depth. In this case the earthquake rays, which are perpendicular to successive coseismals, are by refraction turned upwards, and no longer radiate in straight lines.”

   “The Central Meteorological Observatory has tentatively placed the epicentre at 144.°6 E, 39.°2 N — a result worked out from the coseismals, which were deduced from the times of beginning of the shock at the different meteorological stations.”

   “Now, the average distance between the two inner coseismals is 32 3/4 miles, between the two outer ones (so far as drawn) 35 1/6 miles, and between the first and third 67 1/6 miles.”