# Seismogram Rearrangement as a Perspective Basis for Defining New Attributes
## 2 Materials and Methods
### Elementary Fluctuation--Formal and Real Meaning
The geometry of the infilled basin makes a real resonator, which can create resonances of incident seismic waves and, thus, change the fluctuation pattern in the seismogram. What is interesting to note and to add to such a model of resonator is the urban (built environment) layer, situated on the soil surface, consisting mainly of concrete structures, which changes the wave impedance of the soil surface and affects the seismic picture around the site, even with possibility to amplify seismic effects [1] \"p. 29, Figure 3.1; p. 54, Figure 4.4; p. 145, Figure 5.7\", [8] \"Ch. 3, p. 224, Figure 3.113\". To get an image of possible effects which can stand in the background of seismic phenomena, see [39; 40] \"Figure 4\". The term 'hypocenter' suggests a point-like source of seismic waves. It is actually a relative \"point\", which size depends on distance. Fault interfacing surfaces create a large system ranging from a (few) kilometers (s) to tens or hundreds of kilometers in length. If recorded closely, then each place on the rupturing fault acts as a point source of (its own) seismic waves, so all of them create a very complex picture at the seismic sensor. What's more, an earthquake often starts at one place of the fault, and then the perturbation also propagates along the fault, triggering other strained places to rupture, highly influencing recording conditions and the waveform of seismogram [7] \"article 4.07, Figure 5, p. 2132\". Now, we may have an idea of what all (might) stand behind \"wiggles\" in seismogram, remembering the words of Professor [PERSON], \"understand each wiggle\" [8] \"Ch. 1, p. 6\". It is very difficult to peer through the soil into the seismic processes. In many cases, it turns into a kind of guesswork. A suitable case to study the seismic effects more transparently, not buried in the Earth depths, and to illustrate the effect of increasing seismogram's complexity with the distance is Chelyabinsk/Ural meteorite (small asteroid) impact of 15 February 2013, 17 m in diameter, mass approximately 11,000 tons, which struck Earth's atmosphere at 19.16 km/s speed and exploded in a meteor air burst at about 30 km above Earth's surface, resulting in explosion equivalent to over 470 kilotons of TNT. The air-friction heat evaporated debris, so just 0.05% of the original rock reached the ground as meteorites. This means that the main \"seismic\" mechanism was the air shockwave, of a pretty simple waveform covering vast soil area and triggering detections from monitoring stations as far away as Antarctica. Seismic records, 26 in total, compiled at the GFZ, taken within the span of 227 km to 2197 km, represent a remarkable example of seismogram waveform change with distance. Instead of complex fault rupture processes superimposed to create an intricate waveform, here is a simple \"fault\" mechanism, providing something similar to delta short-impulse excitation. From recording distances, one can infer that the propagation of resulting seismic waves took place mostly through the mantle [41; 42; 43; 44; 45; 46; 47; 48; 49; 50]. Details about the shockwave 'fault' mechanism can be found in [48]. Apart from the GFZ graphical account of the event [43; 45], there are recordings, mostly taken as teleseismic, with arrays in China and the USA [49; 50]. This 'fault' mechanism is, by all means, very specific. It is directional, even to say one-dimensional, without direct material impact, where the whole energy is transferred by the air. It is a kind of'soft' rupture. Quite the skew angle of arrival, and almost graze angle, in combination with shockwave conical pressure front, indicate the area of the 'fault', and time profile of perturbation [43], which is easily seen comparing scales on the \(t\)-axis of this event and any other usual seismogram, e.g., RSN1616. A completely Earth-originating case can be seen in [51] \"Figure 6\". But whatever the processes, in the source or during propagation, they keep the rudimentary and general shape of a random alternation.