Recording earthquakes
	l In 1870s the English geologist John Milne designed a forerunner of modern seismographs. l A simple pendulum and a needle suspended above a smoked-glass plate allowed to distinguish primary and secondary earthquake waves and, basing on their timing, to derive an accurate statement about location of an earthquake source. l The modern seismograph was invented in the early 20th century by the Russian Prince Boris Golitzyn, who improved similar instruments of the 1890's.
			Sixth Workshop on Non-Linear Dynamics and Earthquake Prediction The Abdus Salam ICTP, Miramare
	15/10/2001					4