18:3918:39, 19 November 2016diffhist+343
m
Zhang Heng
The term "seismometer" only applies to devices that record a time signal of earth's motions. Chang Heng's invention was of a "seismoscope," which records the motions but with no sense of time. This is in my seismology textbook, p. 400.
17:0917:09, 25 August 2011diffhist+2
m
Ijen
Someone did their math incorrectly. A circle with a radius of 0.361 km has an area of 0.41 sq km (pi*r^2), not 41 sq km.
18:3918:39, 19 November 2016diffhist+343
m
Zhang Heng
The term "seismometer" only applies to devices that record a time signal of earth's motions. Chang Heng's invention was of a "seismoscope," which records the motions but with no sense of time. This is in my seismology textbook, p. 400.
17:0917:09, 25 August 2011diffhist+2
m
Ijen
Someone did their math incorrectly. A circle with a radius of 0.361 km has an area of 0.41 sq km (pi*r^2), not 41 sq km.