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The earthquake environmental effects (EEEs) around the epicentral area of the Pohang earthquake (Mw-5.4) that occurred on 15 November 2017 have been collected and classified using the Environmental Seismic Intensity Scale (ESI-07 scale) proposed by the International Union for Quaternary Research (INQUA) focus group. The shallow-focus 15 November Pohang earthquake did not produce any surface rupture, but caused extensive secondary environmental effects and damage to life-line structures. This earthquake was one of the most damaging earthquakes during the instrumental seismic era of the Korean Peninsula. The EEEs included extensive liquefaction, ground cracks, ground settlement, localized rockfall, and variation of the water table. The main objective of this paper was to carry forward a comparative assessment of the Pohang earthquake's intensity based on traditional macroseismic scales and the ESI-07 scale. With that objective, this study will also make a substantial contribution to any future revision of the ESI-07 scale, which mostly comprises case studies from Europe and South America. The comparison of the ESI-07 scale with traditional intensity scales similar to the intensity scale used by the Korean Meteorological Administration for the epicentral areas showed 1–2-degree differences in intensity. Moreover, the ESI scale provided a clearer picture of the intensity around the epicentral area, which is mostly agricultural land with a lack of urban units or buildings. This study urges the integration of the traditional and ESI-07 scale for such small magnitude earthquakes in the Korean Peninsula as well as around the world in future. This will predict seismic intensity more precisely and hence provide a more-effective seismic hazard estimation, particularly in areas of low seismic activity. The present study will also provide a useful and reliable tool for the seismic hazard assessment of similar earthquakes around the study area and land-use planning at a local scale considering the secondary effects. [ABSTRACT FROM AUTHOR]

The 28th September 2018 Sulawesi Supershear earthquake (M W 7.5) was one of the deadliest earthquakes in the recent history of Indonesia causing ∼4000 causalities. The earthquake caused a ∼ 177 km long surface rupture along the Palu-Karo fault. Apart from surface rupture, the earthquake caused extensive earthquake environmental effects (EEEs) around the Palu-Donggala area of Central Sulawesi, Indonesia, which includes tsunami, coastal landslide, liquefaction, ground cracks and more than 7300 landslides in hilly areas. Initial post-event analysis and reports assigned a Modified Mercalli Intensity (MMI) of VII to VIII in Palu City and the surrounding area. Building damage and ground effects caused by the earthquake suggested that seismic intensity was understated. Here we applied the EEEs information from field survey data, published reports, and remote sensing tools to determine macroseismic intensity using the Environmental Seismic Intensity (ESI-07) Scale. The ESI-07 intensity derived from the ground effects suggests the maximum intensity of X-XI, which is 3–4° higher than the traditional intensity estimated by the United States Geological Survey (USGS) and the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG). ShakeMaps were generated considering the ESI-07 values. The ShakeMap was compared with the instrumentally derived ShakeMap for the Palu earthquake, which proves that the ShakeMap prepared from the instrumental data or structural damage data is underrated. We argue that proper documentation of the EEEs is necessary for such damaging earthquakes for future earthquake hazard mapping and planning in the study area and other earthquakes in Indonesia. In addition, this will help in defining the on-fault and off-fault damage zone towards reducing the seismic risk of the Palu Donggala area. • Detailed Earthquake Environmental Effects (EEEs) caused by the 28/09/2018 Sulawesi earthquake (M w 7.5) were collected. • The epicentral ESI-07 intensity as well as the site specific intensity were estimated. • The ESI-07 intensity were compared with Skala Intensitas Gempabhumi (SIG), BMKG. • ESI-07 ShakeMap were generated using the Surface Rupture data and ESI-07 values. • The maps can be used to guide efficient and strategic seismic hazard assessment and land use planning. [ABSTRACT FROM AUTHOR]