## The 8 April 1893 Earthquake Data
### Data Collected by Serbian Authorities and Researchers  
The Svilajnac earthquake of 8 April 1893, was the strongest earthquake that has occurred on the territory of Serbia in the past 300 years. Due to its strength and the macroseismic effects it caused on the entire territory of Serbia at the time, the Geological Institute of the Great School (predecessor of the University of Belgrade) held an assembly the next day, 9 April. At this assembly, it was decided: \"1. that the Geological Institute of the Great School undertakes to collect and systematize all data on earthquakes; 2. that the Administrator of the Geological Institute writes a program for describing earthquakes, namely: (a) one for all literate Serbs and (b) for the telegraph authorities; 3. that [PERSON] and [PERSON] goes, on behalf of the Geological Society, to examine the places affected by the earthquake in the valleys of the Morava and Resava rivers; and 4. that [PERSON], [PERSON] and [PERSON] collect newspaper and private individuals' data about the earthquake\". In addition, the Ministers of the Interior and the Economy were asked to hand over all official reports concerning the earthquake in Serbia to the Geological Survey for their use and to request a telegraphic report on the earthquake from all telegraph stations in Serbia according to the questionnaire which was prepared by the Administrator of the Geological Institute. The questionnaire contained the following questions: \"1. what time of day, at which hour, minute, and, if possible, second did the earthquake occur? ; 2. how was it felt, how long did it last, and how did it affect the telegraph station? ; 3. did it affect telegraph equipment in any way? ; 4. did it have any effect on the magnetic needle, how and for how long? ; 5. did it affect the barometer, how and for how long? ; 6. what was the weather like during the earthquake? ; 7. during that period of time, was any peculiar sound heard apart from the noise of the house and the objects in it?\". Thanks to the special efforts of the Ministry of the Interior, a significant number of telegraphic reports were received on 10 April 1893, just two days after the earthquake and on the second day of the Easter holidays. In light of the catastrophic effects of the main shock and the high frequency of aftershocks, and in order to engage as many individuals as possible in the task of gathering the data, a questionnaire with more detailed questions regarding the earthquake and its effects and consequences was created and sent to the public through the Serbian Newspaper on 14 April 1983 (Appendix A). Moreover, to obtain not only as many but also as many accurate answers as possible, the same questionnaire was sent to all teachers in Serbia. In this way, the Geological Institute received numerous data, even from the most remote parts of Serbia. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Source** & **h** & **min** & **s** & **LAT**, \({}^{\circ}\)N & **LON**, \({}^{\circ}\)E & **Depth** & **I0, Radii of Isoseismal Areas [km]** & **Scale** & **M\({}_{\text{S}}\)** & **M\({}_{\text{W}}\)** \\ \hline UNESCO [12] & 13 & 47 & - & 44.3 & 21.3 & - & 9, R9-2, R8-26, R7-55, R6-108, R5-160 & - & - & - \\ \hline [PERSON] et al. [3] & - & - & - & \begin{tabular}{c} (44\({}^{\circ}\) 16\({}^{\prime}\)) \\ 44.267 \\ \end{tabular} & \
\begin{tabular}{c} (21\({}^{\circ}\) 17\({}^{\prime}\)) \\ 21.283 \\ \end{tabular} & 18 & 9 & MCS & 6.5 & - \\ \hline [PERSON] et al. [5] & 13 & 52 & - & 44.12 & 21.30 & 13 &
\begin{tabular}{c} 9, R9-5, R8-26, R7-55, R6-90, R7-55, R6-280, R3-450 \\ \end{tabular} & MSK-64 & 6.6 & - \\ \hline [PERSON] et al. [6] & 13 & 47 & - & 44.3 & 21.3 & - & 9 & - & - & 6.42 \\ \hline RSZS [2] & 13 & 47 & 0 & 44.107 & 21.292 & 8 & 8 & EMS-98 & 5.8 & 5.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Seismological data from various sources for the 8 April 1893 earthquake. The table also shows estimations of \(M_{S}\) and \(M_{W}\) from observed intensities and supposed depths.