To what extent does seismic investigation contribute to our understanding of the Earth's interior structure? Analyze its significance in detail.

Seismic studies and earthquake investigation provide an indirect yet scientific mode to study interior of Earth since they are waves propagating both within (body waves) and on surface (surface waves).

(Diagram showing P-wave and S-wave patterns with labeled hypocenter, showing wave propagation patterns at 14/15 and 10/5 degrees)

Thus the study provide that earth's interior is not of solid uniform density since waves are not refracted everywhere

Fischer p-wave shadow zone provides that there is changing density within the core (s well (outer and inner layer-sphere)

It has helped to understand different densities of crust, mantle and core and discontinuities like Moho, Leoard etc.

However, it is not sufficient and needs to be complemented by other direct and indirect measures like drilling, volcanic eruptions study, temperature, pressure distribution eft.

Significance:

Thus it has emerged as an important tool for analyzing our interior and also contributed to evolution of convection & plate tectonic movement study.