Seismology. Massachusetts Institute of （地震学。）.pdfVIP

Chapter 4 Seismology. 4.1 Historical perspective. 1678 – Hooke Hooke’s Law 
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 ) 1760 – Mitchell Recognition that ground motion due to earthquakes is related to wave propagation 1821 – Navier Equation of motion 1828 – Poisson Wave equation  P S-waves 1885 – Rayleigh Theoretical account surface waves  Rayleigh Love waves 1892 – Milne First high-quality seismograph  begin of observational period 1897 – Wiechert Prediction of existence of dense core (based on meteorites  Fe-alloy) 1900 – Oldham Correct identification of P, S and surface waves 1906 – Oldham Demonstration of existence of core from seismic data 1906 – Galitzin First feed-back broadband seismograph ˇ ´ 1909 – Mohorovicic Crust-mantle boundary 1911 – Love Love waves (surface waves) 1912 – Gutenberg Depth to core-mantle boundary: 2900 km 1922 – Turner location of deep earthquakes down to 600 km (but located some at 2000 km, and some in the air...) 1928 – Wadati Accurate location of deep earthquakes  Wadatai-Benioff zones 1936 – Lehman Discovery of inner core 1939 – Jeffreys Bullen First travel-time tables  1D Earth model 1948 – Bullen Density profile ¨ 1977 – Dziewonski Toksoz First 3D global models 1996 – Song Richards Spinning inner core? Observations: 1964 ISC (International Seismological Centre) — travel times and earthquake locations 1960 WWSSN (Worldwide Standardized Seismograph Network) — (analog records) 1978 GDSN (Global Digital Seismograph Network) — (digital records) 1980 IRIS (Incorporated Research Institutes for Seismology) 117 118 CHAPTER 4. SEISMOLOGY. 4.2 Introduction With seismology1