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[SSS10-P05] Estimation of seismic intensity by questionnaire method in the 2023 Kahramanmaras Earthquake (Mw 7.8), Türkiye
Keywords:Seismic intensity, 2023 Kahramanmaras Earthquake, Türkiye, Questionnaire survey of residents
The 2023 Kahramanmaras Earthquake (Mw 7.8) in Türkiye around 4:17 AM on February 6 (local time) resulted in the loss of 50,096 lives (as of March 20, 2023). This paper presents findings from a questionnaire survey conducted among residents in seven provinces severely affected by this earthquake. This survey aims to clarify shaking distribution factors, and the seismic intensity can be calculated from each person’s answers, so it is possible to grasp shaking intensity distribution with a reasonably high density.
Seismic tremors are determined by the mechanism of the epicenter, the propagation process, and the response of the ground and can vary significantly from one small area to another, even if the epicenter distances are nearly equal. Therefore, detailed seismic intensity distribution within an affected area can best be obtained through questionnaire surveys conducted among individual residents. Consequently, the seismic intensity survey by questionnaire has been done in many earthquakes and microzoning studies have been conducted. Ohta et al. (1979) developed a seismic intensity survey method in Japan using questionnaires based on the Japan Meteorological Agency seismic intensity scale. Internationally, the United States Geological Survey (USGS) has also developed a seismic intensity survey method using questionnaires and operates an Internet-based seismic intensity survey system called Did You Feel It? (Wald et.al., 2011).
Murakami and Kagami (1991) developed questionnaire method to evaluate 12 scale intensity based on MM (Modified Mercalli) Intensity definition, and the method was applied in the 1999 Kocaeli Earthquake survey (Shiono and Koyama, 2000) and the 2015 Gorkha Earthquake survey (Murakami et al., 2016). Applying these methods, we conducted a seismic intensity questionnaire in October 2023 in the seven target provinces, which are Adiyaman, Gaziantep, Hatay, Kahramanmaras, Malatya, Osmaniye, and Sanliurfa. USGS shakemap website (2023) indicates that MMI 8 and around is observed along the earthquake fault from Hatay to Gaziantep, Kahramanmaras, Adiyaman, and Elazig, while MMI 9 or over 9.5 is observed in a more concentrated area from Hatay to Kahramanmaras. According to the report (GÜRBÜZ and ASLAN, 2023), around 307,000 buildings were collapsed, heavily damaged, moderately damaged, or needed for urgent demolition. The number of heavily damaged buildings is especially high in Hatay and Kahramanmaras. We prepared the questionnaire with 32 questions using Google Forms and the ArcGIS Survey 123 system with their address input of provinces, districts, and mahalles (neighborhood) by respondents at the time of the earthquake occurrence (Table 1). The survey was anonymous. The questionnaire format was shared from each Provincial Directorate of National Education to primary, secondary, and high schools. In this survey, we asked how respondents felt the earthquake shaking and observed the damages in their locations and neighborhoods. The number of responses was 14,739. However, after careful examination of the location of the respondents at the time of the earthquake, which they entered, the number of valid responses that could be ascertained down to the province, district, and mahalle, was 12,798 in 11 provinces (Figure 1). Many responses were obtained along the earthquake fault and within urban areas. Using AFAD strong-motion records, we will evaluate the relationship between the questionnaire seismic intensity and the actual ground motion parameters. We are certain that this survey will be essential for further understanding human behavior and damage conditions during an earthquake.
Acknowledgments: This research was supported by the Japan Science and Technology Agency (JST), J-RAPID Collaborative Research/Survey Program for Urgent Research on the 2023 Kahramanmaraş, Turkey, Earthquake. We greatly appreciate the Provincial Directorates of National Education and residents.
Seismic tremors are determined by the mechanism of the epicenter, the propagation process, and the response of the ground and can vary significantly from one small area to another, even if the epicenter distances are nearly equal. Therefore, detailed seismic intensity distribution within an affected area can best be obtained through questionnaire surveys conducted among individual residents. Consequently, the seismic intensity survey by questionnaire has been done in many earthquakes and microzoning studies have been conducted. Ohta et al. (1979) developed a seismic intensity survey method in Japan using questionnaires based on the Japan Meteorological Agency seismic intensity scale. Internationally, the United States Geological Survey (USGS) has also developed a seismic intensity survey method using questionnaires and operates an Internet-based seismic intensity survey system called Did You Feel It? (Wald et.al., 2011).
Murakami and Kagami (1991) developed questionnaire method to evaluate 12 scale intensity based on MM (Modified Mercalli) Intensity definition, and the method was applied in the 1999 Kocaeli Earthquake survey (Shiono and Koyama, 2000) and the 2015 Gorkha Earthquake survey (Murakami et al., 2016). Applying these methods, we conducted a seismic intensity questionnaire in October 2023 in the seven target provinces, which are Adiyaman, Gaziantep, Hatay, Kahramanmaras, Malatya, Osmaniye, and Sanliurfa. USGS shakemap website (2023) indicates that MMI 8 and around is observed along the earthquake fault from Hatay to Gaziantep, Kahramanmaras, Adiyaman, and Elazig, while MMI 9 or over 9.5 is observed in a more concentrated area from Hatay to Kahramanmaras. According to the report (GÜRBÜZ and ASLAN, 2023), around 307,000 buildings were collapsed, heavily damaged, moderately damaged, or needed for urgent demolition. The number of heavily damaged buildings is especially high in Hatay and Kahramanmaras. We prepared the questionnaire with 32 questions using Google Forms and the ArcGIS Survey 123 system with their address input of provinces, districts, and mahalles (neighborhood) by respondents at the time of the earthquake occurrence (Table 1). The survey was anonymous. The questionnaire format was shared from each Provincial Directorate of National Education to primary, secondary, and high schools. In this survey, we asked how respondents felt the earthquake shaking and observed the damages in their locations and neighborhoods. The number of responses was 14,739. However, after careful examination of the location of the respondents at the time of the earthquake, which they entered, the number of valid responses that could be ascertained down to the province, district, and mahalle, was 12,798 in 11 provinces (Figure 1). Many responses were obtained along the earthquake fault and within urban areas. Using AFAD strong-motion records, we will evaluate the relationship between the questionnaire seismic intensity and the actual ground motion parameters. We are certain that this survey will be essential for further understanding human behavior and damage conditions during an earthquake.
Acknowledgments: This research was supported by the Japan Science and Technology Agency (JST), J-RAPID Collaborative Research/Survey Program for Urgent Research on the 2023 Kahramanmaraş, Turkey, Earthquake. We greatly appreciate the Provincial Directorates of National Education and residents.