Journal of Asian Earth Sciences 220 (2021) 104936 Available online 1 September 2021 1367-9120/© 2021 Published by Elsevier Ltd. Importance of real-time PGV in terms of lead-time and shakemaps: Results using 2018 M L 6.2 & 2019 M L 6.3 Hualien, Taiwan earthquakes Himanshu Mittal a, b, 1 , Benjamin Ming Yang b , Tai-Lin Tseng b , Yih-Min Wu b, c, d, * a Amity Center of Ocean-Atmospheric Science and Technology (ACOAST), Amity University, Jaipur, Rajasthan 303002, India b Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan c Institute of Earth Sciences, Academia Sinica, Taipei 11529, Taiwan d Research Center for Future Earth, National Taiwan University, Taipei 10617, Taiwan A R T I C L E INFO Keywords: Earthquake Early warning Peak ground acceleration Peak ground velocity P-Alert Shakemaps ABSTRACT Two earthquakes having almost the same magnitude occurred in the Hualien area of Taiwan in 2018 and 2019. The 2018 earthquake had a magnitude M L 6.2 produced severe destruction; however, the 2019 earthquake (M L = 6.3) did not cause any severe damage. The P-Alert Strong Motion Network provides real-time shakemaps, in addition, to earthquake early warning (EEW) in terms of lead-time. Each instrument provides a different lead- time using peak ground acceleration (PGA) and peak ground velocity (PGV). During both the events, the in- struments reported a lead-time of 1.5 to 8.0 s in the epicentral region. This network system also generated high- quality shakemaps during both earthquakes. The shakemaps showed that the higher PGAs are concentrated in the epicentral region for the 2018 and 2019 earthquakes. The lower PGA contour (≥25 Gal) extended to a broader area, including Taipei, during the 2019 earthquake compared to the 2018 earthquake. However, PGV shakemaps display a different pattern. The higher PGV values (more than 17 cm/s) are observed in the epicentral region during the 2018 earthquake (locations suffering building collapse) compared to the 2019 earthquake, suggesting that PGV correlates better with damage distribution as compared to the PGA. The PGV shakemap, currently only available for the P-Alert network, provides crucial information that complements the PGA issued by the offcial agency in Taiwan. 1. Introduction Being located on the junction of two tectonic plates, Taiwan Island is one of the seismically active areas in the world. The Philippine Sea plate (PSP) moves toward the Eurasian plate (EP) at a velocity of approxi- mately 7 cm/year (Yu et al., 1997). Due to the collision of these two plates, the accumulated stresses are released, causing earthquakes in and around Taiwan Island. In addition to this collision, several other local faults in western and southern Taiwan are also responsible for the frequent earthquake activity in Taiwan. Taiwan Island has a long history of earthquakes. The largest recorded earthquake in the last two decades is the Chi-Chi earthquake of September 21, 1999, which claimed more than 2400 lives (Wu et al., 2004). The Nantou earthquakes of 2013 caused few damages in the Nantou area, Taiwan, claiming fewer lives (Hsieh et al., 2014). The recent earthquakes of 2016 caused widespread damage in southern Taiwan (Wu et al., 2016). The 2016 earthquake with a magnitude M L 6.4 occurred at a depth of 16.7 km and claimed 117 lives. All these earthquakes were caused by the active seismic faults in western and southern Taiwan. Hualien area, on the contrary, is situated in eastern Taiwan, where earthquake activity is due to the oblique subduction of the PSP under the EP (Koulakov et al., 2014; Shyu et al., 2011). The collision of these two plates gives rise to numerous earthquakes in the Hualien area (Shyu et al., 2016), some of which have a magnitude greater than 4. The major reverse fault, namely, the Milun fault located on the western boundary of the Milun tableland, is mapped in this region (Fig. 1). This Milun fault had been quiet for the last two decades since the massive earthquake struck Hualien in 1951 (Shyu et al., 2005). In recent times, two mod- erate magnitude earthquakes, namely February 6, 2018 (M L 6.2) and April 18, 2019 (M L 6.3), occurred again in this region. The earthquake of 2018 caused signifcant damage in the epicentral region compared to the earthquake of 2019, although the magnitude of the 2019 earthquake * Corresponding author at: Dept. Geosciences, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan. E-mail address: drymwu@ntu.edu.tw (Y.-M. Wu). 1 Presently at National Center for Seismology, Ministry of Earth Sciences, Lodhi Road, New Delhi 110003, India. Contents lists available at ScienceDirect Journal of Asian Earth Sciences journal homepage: www.elsevier.com/locate/jseaes https://doi.org/10.1016/j.jseaes.2021.104936 Received 13 August 2020; Received in revised form 19 August 2021; Accepted 22 August 2021