Based on earthquake data, how we can define the type of rocks and minerals within the earth?
Dear Dr. Doloei
one of main source of information is the velocity of earthquake waves, specially P waves that is a good source of information on the density of rocks in the crust. comparison with experimental data of P-wave velocity in various rocks types is also used.
Dear Dr. Javan,
In attachment, you will find a *.pdf document about the P- and S- velocity for each type of rock which can help you in this way.
With Kind Regards,
Hossein Kianimehr
Dear Dr. Doloei,
I recommend a lecture on Site Characterisation in New Zealand: Latest research and best practice, https://www.youtube.com/watch?v=5LKS9yiLdDs&feature=youtu.be
In his lecture, Dr. Liam Wotherspoon presented geotechnical and geophysical investigation methods , along with the importance of the knowledge of underlying geology. Hopefully You will find this helpful.
Best regards,
Borko
Lots of earthquake stations today, therefore, lots of data to study using the velocity of the waves. Scientists know a lot more information than previously and there is more to study. The data displayed in the lecture suggested by Dr. @ Borko Bulajic are amazing!
In short, this is done by finding correlations between seismic wave velocity, for instance, and rock type.
1. We determine anomalies of density through the EGM 2008 geoid anomalies using the Professor Moritz’s decision of the inverse gravity problem [Moritz H. 1990. The Figure of the Earth. Theoretical Geodesy and the Earth's Interior. Wichmann, Karlsruhe]. Anomalies of density are in percent relatively to PREM. The Stock’s formula (Theory of the Figure of the Earth) is used for determination of depth of the disturbing body. Comparison with the seismic tomography shows coincidence in many cases. Some discrepancies are inevitable, because these methods characterize different physical properties of geological environment. Namely: gravitational force causes the geoid anomaly but seismic property of the bedrock (elasticity, hardness) causes the velocity anomaly of the seismic signal.
Antarctica and Ukraine are our main areas of researches.
2. Dear ResearcGate! I never was as a member of the Chinese Academy of Geological Sciences. I work within the National Academy of Sciences of Ukraine.
Dear all,
Hello
All your answers are nice. And I have to add one more hint to this question. When an earthquake with a large magnitude happen, the released energy can propagates within earth structure and bring a lot of information when arriving in a seismic station. So processing recorded waveform of an earthquake at different stations can help seismologist to derive physical and chemical properties along ray paths. So if we consider the seismic velocity as one of key property of the layers structure which has a relation with type of rocks then talking about type of rocks can be easy after waveform analysis beneath seismic stations.