## 1 Introduction  
Earthquakes can inflict heavy damage and human casualties. Related disciplines have studied earthquakes to widen and deepen understanding of the phenomenon. There is a natural hierarchy in this complex study. At the top is seismology (geoscience), which studies earthquakes as intrinsic processes (see, e.g., [1, 2, 3]). The next layer, which relies on the findings and extensive knowledge of the previous discipline, deals with earthquake risk reduction and hazard assessment, creating a basis for the majority of activities in societies that can be affected by earthquakes. There is immense literature related to this area of knowledge, which indicates a high interest of humankind in these effects. This work presents and briefly discusses just a few examples, chosen in a semi-random manner, to help create a representation in this area. For example, the German GFZ (GeoForschungsZentrum,(eng) Research Centre for Geosciences) provides seismic hazard maps [4] as products of the Global Seismic Hazard Assessment Program started in 1993 [5]. The basis for these hazard maps is the seismic database. As for particular research in this area, the references [6; 7; 8; 9; 10; 11] are typical and illustrative. There is also a large amount of general literature, including the authors' favorite [12], which covers the transition from hazard to seismic-resistant civil engineering, aimed to alleviate the seismic vulnerability of the built environment [13; 14; 15]. The acquired knowledge gradually improves planning, designing, and constructing structures according to the developing standards of earthquake resilience [12]. The perpetual updating of regulations and standards for designing and building structures is derived from the study of earthquakes themselves and the effects they cause on existing structures. A seismogram contains almost all one can really know about an earthquake, apart from the effects people see, feel, or suffer. It is a recorded waveform of seismic effects at a site, representing fluctuations of related physical (mechanical) quantities as the result of many complex processes taking place in the so-called \"information chain\" of seismology, with many interrelated sub-systems such as the seismic source, wave propagation through the Earth, distortion by other seismic signals, and the influence of seismic sensors, recorders, and processing techniques on the seismogram [1] \"Ch. 1, Figure 1.2, p. 6\". An excellent survey of all the phenomena involved can be found in [1] \"Ch. 11\". The influence of propagation conditions on a waveform's appearance in different seismograms that all originate from the same event can be seen in [16] \"Figures 5 and 6\". Therefore, seismogram databases contain all the accumulated intrinsic knowledge of seismicity, where earthquakes are classified according to various criteria, i.e., parameters. Databases are the main sources of seismic information for experts from various branches of knowledge interested in earthquakes and their effects, who then transform these raw data into respective findings, rules, recommendations, and assessments, often incorporated into regulations. These experts include geophysicists, seismologists and observatory personnel, civil engineers, disaster managers, risk planners, urban planners, and governments, not to mention related researchers, students, and training personnel [1] \"Ch. 1, pp. 29\", [12; 17]. Any earthquake in a database is represented by at least one or up to several seismograms and accompanying parameters. Seismic databases can be conditionally categorized as general and specific by content, and as global and local by cover. A typical example of general/global is the PEER Ground Motion Database [18]. The use of the PEER database motivated the authors to conduct this research. Accordingly, this database is the main reference and the main frame for seeking solutions.