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R. Mallet, an Irish mechanic goes to Italy to study the damage caused by an earthquake near Naples.
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F. Cecchi builds the first time - recording seismograph in Italy
Then higher quality instruments were then developed by British scientists in Japan -
First seismograph was installed in North America at Lick Observatory near San Jose, California
It then recorded the 1906 San Francisco earthquake
E. Wiechert developed the first seismometer -
B. B. Galitzen develops electromagnetic seismograph
All modern seismographs are electromagnetic -
R. Oldham identifies P-, S- and surface waves in earthquake records
Detects liquid in earth’s core from absence direct of body waves at certain distances. -
In 1928 K. Wadati first presented evidence of deep earthquakes located along dipping zones of seismicity where crustal plates plates subduct into the mantle.
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Computers with larger dataset begins too have problems in the 1960s:
Routine earthquake locations
inverse problems
Theoretical seismographs
Crustal imaging using artificial sources
Normal modes
Slip distribution on fault -
First digital and global seismographs installed
Digital portable seismographs used for special studies ( source scaling and site response)
Digital seismic data established -
Elastic wave propagation in solid materials is developed by Cauchy, Poisson, Stokes, Rayleigh and others.The describe Primary and Secondary body waves (P and S waves) and surface waves.
