# Seismogram Rearrangement as a Perspective Basis for Defining New Attributes
## 1 Introduction
### Purpose and Categories of Attributes  
A seismogram is usually a very complex transient. It contains, or hides, all the available information about an earthquake but taken at the (recording) site. As such, it is cumbersome and intricate for direct use. In addition, not all experts are interested in the information the seismogram waveform brings with them, but they seek some aspects that are the most important for their needs. So, it asks for processing, to a certain extent, to find out needed characteristics, often called attributes or features, which carry particular significance for users and reveal interesting content from raw recordings. Here it is accepted the widest definition of seismic attribute, as any information of interest that can be derived from raw seismic data [11]. There are many references involving the notion of'seismic attribute' [12; 13; 14; 15; 16], often giving the definition of the issue. What can be noticed is a slight evolution in the meaning of the seismic attribute [12; 13]. In close relation to the definition stands the issue of attribute classification [12; 16]. Either with respect to definition or classification, this research relies on the broader meaning of both notions. Only a few characteristics can be extracted directly from a seismogram, but it does not mean simply picking up the item(s) because it is not the result of a passive perception of details, but rather depends on the researcher's recognition ability, backed by his/her knowledge and experience about waveform background, and many other conditions [8] \"Ch. 1, Section 1.3, Ch. 11\". It may seem that the reading is burdened by subjective factors, but provided a skilled analyst instead of, e.g., a novice, this makes the description objective, quantified, and comparable to other cases because the examiner performs according to the prescribed procedure. In [8] \"Ch. 1, Section 1.3\", it is explicitly stated that to \"provide properly processed and interpreted seismograms under these diverse conditions, it is necessary to establish protocols for all aspects of observatory operation that may affect the seismologicaldata itself\". There are other interesting proposals regarding procedures of seismogram interpretation [17]. Even for the most skillful researcher, much of the content in seismograms remains hidden. To extract such information, various (post)processing techniques are used, either performed by humans (graphically numerical methods) or by machines (usually computer programs), up to artificial intelligence [18]. In both cases, techniques stem from respective algorithms. In the first case, the human is functioning as a'machine' (following the strict protocol). There are (too?) many attributes [19], and each one is dedicated to something particular in seismogram or any other random signal. Such a heap of attributes needs categorization. The grade \"too\" and question mark definitely prove that the seismogram is a very complex matter. They can be roughly classified into parametric and functional attributes. Parametric ones can be further divided into single-parametric and group-parametric. Single-parametric can be local and general, with the latter determined from the whole seismogram. Examples of local single-parametric are the peak-to-peak max span (\(B\)), and the period (\(T\)), given in, e.g., [8] \"Ch. 3, p. 47, Figure 3.19, Figure 3.28\" while general single-parametric are, e.g., 5-95% duration [20; 21; 22], seismogram energy [8] \"Ch. 3\" etc. The root-mean-square acceleration  
\[a_{rms}=\left[\frac{1}{T_{2}-T_{1}}\int_{T_{1}}^{T_{2}}a^{2}(t)dt\right]^{1/2} \tag{1}\]  
is an important, and also interesting single-parametric attribute, which, implicitly, contains other attributes (parameters): \(T_{1}\) and \(T_{2}\), where the size and location of the interval \(T_{2}-T_{1}\) strongly influence the value of \(a_{rms}\) for a transient signal like seismogram, so \(T_{1}\) and \(T_{2}\) commonly chosen to exclude insignificant shaking.