# NPP-VIIRS DNB Daily Data in Natural Disaster Assessment: Evidence from Selected Case Studies
## 2 Materials and Methods  
### Event Selection  
According to the Emergency Events Database (EM-DAT) launched by the Centre for Research on the Epidemiology of Disasters (CRED) of the U.S., the top 10 types of major natural hazards in the world ranked by the number of deaths since 1900 are: drought, epidemic, floods, earthquakes, storms, extreme temperature, volcanic activity, landslides, fog, and wildfire [44]. In this study, we selected three major disaster types: floods, earthquakes, and storms. We did not attempt to assess other types of disasters because droughts, epidemics, extreme temperatures, and fogs are not likely to directly cause NTL reduction; volcanic activity and wildfire are accompanied by serious smoke; and landslides typically happen in undeveloped mountainous areas with little light. For each of the three types of disasters, we selected two typical disastrous events that had significant impacts on people. The study areas contained the most affected areas in these disasters. As the daily NPP-VIIRS DNB data have only been available since 18 July 2012, we selected disasters after this date. Table 1 lists the basic information of the disaster events that were selected and Figure 1 illustrates the locations and land cover categories of each study area. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Disaster Type** & **Event** & **Time** & **Study Area** \\ \hline \multirow{4}{*}{Earthquake} & Gorkha Nepal & 25 April 2015 & Kathmandu and the surrounding area \\  & Earthquake & 06:11 a.m. (UTC) & (Area size: 48 km \(\times\) 57 km), Nepal \\ \cline{2-4}  & Central Italy & 24 August 2016 & Accumoli, Amatrice, Norcia, and \\  & Earthquake & 01:36 a.m. (UTC) & Arquata Del Tronto, Italy \\ \hline \multirow{4}{*}{Storm} & Hurricane Maria & 20 September 2017 & Puerto Rico, U.S. \\  & Hurricane Maria & 10:15 a.m. (UTC) & Visakhapatnam, India \\ \cline{2-4}  & Tropical Cyclone & 12 October 2014 & \\ \cline{1-1}  & Hudhud & 04:30 p.m. (UTC) & \\ \hline \multirow{4}{*}{Flood} & Louisiana Flood & 11 August 2016–16 & East Baton Rouge Parish and Livingston \\ \cline{2-4}  & Louisiana Flood & August 2016 & Parish, U.S. \\ \cline{1-1} \cline{2-4}  & Yulin Flood & 25 July 2017–26 July 2017 & \\ \cline{1-1} \cline{2-4}  & & 2017 & Suide, China \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The selected disaster events and study area. The Gorkha Nepal Earthquake in 2015 had a magnitude of 7.8 and caused 8790 deaths and 22,300 injuries in Nepal [45]. The epicenter was in Barpak, Gorkha district (Figure 1a) and it had a depth of 15 km [2]. The study area contains Kathmandu (the capital of Nepal), Bhaktapur, and parts of Nuwakot, Sindhupalchok, Kavepalanchok, Lalitpur, Makwanpur, and Dhading. The earthquake caused 1222 deaths in Kathmandu, 333 deaths in Bhaktapur, and a large number of houses in the areas to collapse [45]. The Central Italy Earthquake in 2016 was a 6.2 magnitude earthquake that hit central Italy. Although it had a lower magnitude than the Gorkha Nepal Earthquake, it had a shallower epicenter depth of 4.4 km causing more violent ground shaking. The study area contains the four worst-affected counties in Central Italy: Accumoli (epicenter), Amatrice, Norcia, and Arquata Del Tronto. According to the news report [46], 80% of the old town center in Amatrice was destroyed and almost every building  
Figure 1: The location and land cover categories from the National Geomatics Center of China of each study site of the six disaster events: (**a**) Gorkha Nepal Earthquake, (**b**) Central Italy Earthquake, (**c**) Hurricane Maria, (**d**) Tropical Cyclone Hud Hudud, (**e**) Louisiana Flood, and (**f**) Yulin Flood. was cracked. As of 26 August 2016, the earthquake had caused 297 deaths with 234 in Amatrice, 11 in Accumoli, and 49 in Arquata del Tronto [47]. Hurricane Maria was the strongest storm that attained landfall in Puerto Rico in the past 85 years.