## 4 Impact of the 6 February 2023 Earthquakes on Structures and Earthquake Debris
### Earthquake Debris Composition and Volume  
Based on an estimation made by the United Nations Development Programme (UNDP) [52], the 6 February 2023 earthquakes caused between 116 and 210 million tonnes of debris which constitutes one of the largest debris volumes recorded from a disaster associated with or caused by a natural hazard since the 17 January 1994, Mw = 6.7 Northridge (Southern California, United States) earthquake (Table 2). Furthermore, [PERSON] et al. [53] estimated the demolition debris generated by the 6 February 2023 earthquakes by applying two different approaches. The first one takes into account the number of the earthquake-affected population, the average housing area per person, and the amount of demolition debris generated per unit housing area. Based on this information, [PERSON] et al. [53] predicted that between 520 and 840 million tons of debris were generated by the earthquakes (Table 2). The second approach takes into account the amount of damaged buildings and in particular the estimated number of collapsed or damaged buildings, the proportions of reinforced concrete and masonry structures, and the average building areas of reinforced concrete and masonry structures, considered as the dominant building types in the earthquake-affected area. Based on this information, [PERSON] et al. [53] predicted that between 450 and 920 million tons of debris were generated by the earthquakes (Table 2). \begin{table}
\begin{tabular}{c c c c} \hline
**Provines Affected by the 6 February 2023 Earthquakes** & **Collapsed and Severely Damaged and Urgently Demolished Houses** & **Moderately Damaged Houses** \\ \hline Adana & 2952 & 11,768 & 71,072 \\ Adiyaman & 56,256 & 18,715 & 72,729 \\ Diyarbakar & 8602 & 11,209 & 113,223 \\ Elazg & 10,156 & 15,220 & 31,151 \\ Gaziantep & 29,155 & 20,251 & 236,497 \\ Kahramanmaras & 99,326 & 17,887 & 161,137 \\ Malatya & 71,519 & 12,801 & 107,765 \\ Hatay & 215,255 & 25,957 & 189,317 \\ Kilis & 2514 & 1303 & 27,969 \\ Osmaniye & 16,111 & 4122 & 69,466 \\ Sanhurfa & 6163 & 6041 & 199,401 \\ Total & 518,009 & 131,577 & 1,279,727 \\ \hline \end{tabular}
\end{table} 
Table 1: Results of the post-event buildings inspection and damage assessment in the 11 provinces of the southeastern part of Turkey based on the data presented by the Ministry of Environment, Urbanization and Climate Change of Turkey until 6 March 2023 [15]. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline
**Date** & **Earthquake** & **Affected Country** & **M** & **I** & **DV** & **Source for DV** & **HL** & **IP** & **TA** \\ \hline
17 January 1994 & Northridge & USA & 6.7 & IX & 2 & [55] & 60 & 67,000 & 27,000 \\
17 January 1995 & Kobe & Japan & 6.9 & XI & 15 & [56] & 5297 & 34,492 & 541,636 \\
17 August 1999 & Izmit & Turkey & 7.6 & X & 13 & [5] & 17,127 & 43,953 & 1,358,953 \\
23 October 2004 & Chénetsu & Japan & 6.6 & IX & 0.6 & [57] & 40 & 3183 & 62,183 \\
26 December 2004 & India Ocean & Indonesia * & 9.2 & IX & 10** & [58] & 165,708 & - & 523,898 \\
12 May 2008 & Sichuan & China & 7.9 & XI & 380 & [4] & 87,476 & 366,596 & 45,976,596 \\
6 April 2009 & L’ Aquila & Italy & 6.3 & X & 1–3 & [59; 60; 61] & 295 & 1000 & 56,000 \\
12 January 2010 & Haiti & Haiti & 7.0 & X & 23–60 & [62] & 222,570 & 300,000 & 3,700,000 \\
11 March 2011 & Tohoku & Japan & 9.1 & IX & 24.9 & [63] & 19,846 & 5933 & 362,887 \\
22 February 2011 & Christchurch & New Zealand & 6.1 & XI & 8 & [64] & 181 & 1500 & 301,500 \\ \hline \end{tabular}
\end{table} 
Table 2: The volume of debris produced by earthquake disasters worldwide. (M: moment magnitude, I: Intensity, DV: Debris volume in million tonnes; HL: Human losses, IP: Injured people, TA: Total affected people). Information about M, I, HL, IP, and TA are extracted from the International Disaster Database (EM-DAT) [54]. The sources of debris volume (DV) estimation are presented in the table. The aforementioned data reveals that the 6 February 2023 earthquakes in Turkey resulted in a very large debris volume, whose values show a wide range depending on the estimation method.