The crust of the Earth is made up of rocks and soils, the latter produced by the weathering of rocks. Therefore, rocks and soils contain the same chemical elements, and their mineral composition is also similar. In addition, soils contain organic matter.
Rocks are defined as incoherent, naturally formed substances, mostly composed of minerals. They can be classified as igneous, sedimentary, and metamorphic, depending on their origin.

Seismology is, in the truest sense of the word, a global science, not limited to political boundaries. Thus, it can only be effectively practiced through international cooperation.
Seismology is primarily an observational science. Quantitative measurements of seismic ground motion as a function of time require physically well defined, continuously recording instruments. Suitable seismographs of different design principles became available at the end of the 19th century. In the following years, a considerable number of seismograph stations were installed at sites around the globe. At the dawn of this century, some of these stations celebrate their 100th anniversary, as does the International Association of Seismology and Physics of the Earth’s Interior (IASPEI).

1.    Suggested methods for determining tensile strength of rock materials (1978)
2.    Suggested methods for determining the strength of rock materials in triaxial compression (1978)
3.    Suggested methods for determining the uniaxial compressive strength and deformability of rock materials (1979)
4.    Suggested methods for determining shear strength (1974)