Geospatial Assessment of the Post-Earthquake Hazard of the 2017 Pohang Earthquake Considering Seismic Site Effects

The 2017 Pohang earthquake (moment magnitude scale: 5.4) was South Korea’s second strongest earthquake in decades, and caused the maximum amount of damage in terms of infrastructure and human injuries. As the epicenters were located in regions with Quaternary sediments, which involve distributions of thick fill and alluvial geo-layers, the induced damages were more severe owing to seismic amplification and liquefaction. Thus, to identify the influence of site-specific seismic effects, a post-earthquake survey framework for rapid earthquake damage estimation, correlated with seismic site effects, was proposed and applied in the region of the Pohang earthquake epicenter. Seismic zones were determined on the basis of ground motion by classifying sites using the multivariate site classification system. Low-rise structures with slight and moderate earthquake damage were noted to be concentrated in softer sites owing to the low focal depth of the site, topographical effects, and high frequency range of the mainshocks.


Change in the First Paragraph of Introduction
The authors wish to supplement the citation, which was existing references (reference #1 and #2 in the changed manuscript), to clarify the reference of major events of 2017 Pohang Earthquake, as follows: Original text: "The 2017 Pohang earthquake occurred on 15 November 2017, in Heunghae, Pohang in the North Gyeongsang Province in South Korea. [ . . . ] The clusters of epicenters were located along an unknown branch of the fault system as well as distributed across the Heunghae basin. Although the degree of seismic amplification of the 2017 Pohang earthquake was lower than that of the 2016 Gyeongju earthquake, the Pohang earthquake damage was more severe as its epicenters were spatially concentrated on unconsolidated Quaternary sediments (alluvial fans and granite wash)." to the correct version, as follows: an unknown branch of the fault system as well as being distributed across the Heunghae basin [2]. Although the degree of seismic amplification of the 2017 Pohang earthquake was lower than that of the 2016 Gyeongju earthquake, the Pohang earthquake damage was more severe as its epicenters were spatially concentrated on unconsolidated Quaternary sediments (alluvial fans and granite wash) [2]." Figure 1 of Introduction Figure 1 described the epicenters and fault-plane solutions of major events of the 2017 Pohang Earthquake, and also visualized the spatial distribution of all aftershock epicenter (until July 2017) without the correct reference. The epicenters and fault-plane solutions were uncertain and needed further research by the seismologist. Thus, the correct epicenter of major events (1 mainshock and 6 aftershocks) was revised as Figure 1 using the officially published information by the Korean Meteorological Administration (reference #1 in the changed manuscript) [2]. Additionally, the high-resolution satellite image with shaded by terrain (DEM) was applied. The author wishes to make the following correction to this paper [1]. Due to the errata, replace:

Change in
to the correct version, as follows: Revised text: "The 2017 Pohang earthquake occurred on 15 November 2017, in Heunghae, Pohang in the North Gyeongsang Province in South Korea [1]. […] The clusters of epicenters were located along an unknown branch of the fault system as well as being distributed across the Heunghae basin [2]. Although the degree of seismic amplification of the 2017 Pohang earthquake was lower than that of the 2016 Gyeongju earthquake, the Pohang earthquake damage was more severe as its epicenters were spatially concentrated on unconsolidated Quaternary sediments (alluvial fans and granite wash) [2]." Figure 1  without the correct reference. The epicenters and fault-plane solutions were uncertain and needed further research by the seismologist. Thus, the correct epicenter of major events (1 mainshock and 6 aftershocks) was revised as Figure 1 using the officially published information by the Korean Meteorological Administration (reference #1 in the changed manuscript) [2]. Additionally, the highresolution satellite image with shaded by terrain (DEM) was applied. The author wishes to make the following correction to this paper [1]. Due to the errata, replace:  Table 1

of Introduction
We have found the corresponding error in Table 1, likewise, in Figure 1. Table 1 and Figure 1 provide only the seismological information of major events of the 2017 Pohang Earthquake. To apply the correct time of occurrence, the coordinate of the epicenter, depth, magnitude (ML), Table 1 should be changed. The modification of Table 1 (Figure 1) was officially published information by the Korean Meteorological Administration (reference #1 in the changed manuscript) [2]. to the correct version, as follows:

Change in Table 1 of Introduction
We have found the corresponding error in Table 1, likewise, in Figure 1. Table 1 and Figure 1 provide only the seismological information of major events of the 2017 Pohang Earthquake. To apply the correct time of occurrence, the coordinate of the epicenter, depth, magnitude (M L ), Table 1 should be changed. The modification of Table 1 (Figure 1) was officially published information by the Korean Meteorological Administration (reference #1 in the changed manuscript) [2]. to the correct version, as follows:

Change in Figure 3
In Figure 3, the spatial distribution of all aftershock epicenters was also visualized. This modification corresponds with changes #2 and #3. Thus, the epicenters of seven major events were also modified. Additionally, five multi-layered geo-data were visualized on the same area to help to understand the spatial modeling of geo-data. In Figure 3, the spatial distribution of all aftershock epicenters was also visualized. This modification corresponds with changes #2 and #3. Thus, the epicenters of seven major events were also modified. Additionally, five multi-layered geo-data were visualized on the same area to help to understand the spatial modeling of geo-data. to the correct version, as follows: to the correct version, as follows:

Change in Figure 9
Figure 9 shows the spatial comparison between T G -based seismic zonation and earthquake damage category of buildings. Additionally, the spatial distribution of all aftershock epicenter was also visualized on the spatial comparison map to help reader to understand the epicenter. Thus, the correct epicenter of major events (corresponding changes to Figure 1 and Table 1) was also modified.  damage category of buildings. Additionally, the spatial distribution of all aftershock epicenter was also visualized on the spatial comparison map to help reader to understand the epicenter. Thus, the correct epicenter of major events (corresponding changes to Figure 1 and Table 1) was also modified. to the correct version, as follows: to the correct version, as follows: Figure 9. Spatial comparison between TG-based seismic zonation and earthquake damage category of buildings.
to the correct version, as follows: Figure 9. Spatial comparison between TG-based seismic zonation and earthquake damage category of buildings. Figure 6. Spatial comparison between T G -based seismic zonation and earthquake damage category of buildings.

Change in References (Reference #2)
The accessed date of reference #1 in the reference list should be changed to apply the up-to-date earthquake record. And reference #2 in the reference list should be modified to clarify the correct English title, which is the Korean report (reference #2 in the changed manuscript) [3].