Seismologists - Highlights of The History of Seismology

Highlights of The History of Seismology

Some milestones in the development of seismology are:

Early speculations on the natural causes of earthquakes in the writings of Thales of Miletos (ca. 585 B.C.E.), Anaximenes of Miletos (ca. 550 B.C.E.), Aristotle (ca. 340 B.C.E.) and Zhang Heng (132 C.E.).

In 132 C.E., Zhang Heng of China's Han dynasty designed the first known seismoscope.

In 1664 Athanasius Kircher argued that eathquakes were caused by the movement of fire within a system of channels inside the Earth.

In 1703 Martin Lister (1638 to 1712) and Nicolas Lemery (1645 to 1715) proposed that earthquakes were caused by chemical explosions within the earth.

The Lisbon earthquake of 1755, coinciding with the general flowering of science in Europe, set in motion intensified scientific attempts to understand the behaviour and causation of earthquakes. The earliest responses include work by John Bevis (1757) and John Michell (1761). Michell determined that earthquakes originate within the Earth and were waves of movement caused by "shifting masses of rock miles below the surface".

From 1857 Robert Mallet laid the foundation of instrumental seismology and he carried out seismological experiments using explosives.

In 1897, Emil Wiechert's theoretical calculations led him to conclude that the Earth's interior consists of a mantle of silicates, surrounding a core of iron.

In 1906 Richard Dixon Oldham identified the separate arrival of P-waves, S-waves and surface waves on seismograms and found the first clear evidence that the Earth has a central core.

In 1910, after studying the 1906 San Francisco earthquake, Harry Fielding Reid put forward the "elastic rebound theory" which remains the foundation for modern tectonic studies. The development of this theory depended on the considerable progress of earlier independent streams of work on the behaviour of elastic materials and in mathematics.

In 1926 Harold Jeffreys was the first to claim, based on his study of earthquake waves, that below the crust, the core of the Earth is liquid.

In 1937 Inge Lehmann determined that within the earth's liquid outer core there is a solid inner core.

By the 1960s earth science had developed to the point where a comprehensive theory of the causation of seismic events had come together in the now well-established theory of plate tectonics.