Real-Time Production of PGA, PGV, Intensity, and Sa Shakemaps Using Dense MEMS-Based Sensors in Taiwan

Abstract

Using low-cost sensors to build a seismic network for earthquake early warning (EEW) and to generate shakemaps is a cost-effective way in the field of seismology. National Taiwan University (NTU) network employing 748 P-Alert sensors based on micro-electro-mechanical systems (MEMS) technology is operational for almost the last 10 years. This instrumentation is capable of recording the strong ground motions of up to ± 2g and is dense enough to record the near-field ground motion. It has proven effective in generating EEW warnings and delivering real-time shakemaps to the concerned disaster relief agencies to mitigate the earthquake-affected regions. Before 2020, this instrumentation was used to plot peak ground acceleration (PGA) shakemaps only; however, recently it has been upgraded to generate the peak ground velocity (PGV), Central Weather Bureau (CWB) Intensity scale, and spectral acceleration (Sa) shakemaps at different periods as value-added products. After upgradation, the performance of the network was observed using the latest recorded earthquakes in the country. The experimental results in the present work demonstrate that the new parameters shakemaps added in the current work provide promising outputs, and are comparable with the shakemaps given by the official agency CWB. These shakemaps are helpful to delineate the earthquake-hit regions which in turn is required to assist the needy well in time to mitigate the seismic risk.

A Review on the Development of Earthquake Warning System Using Low-Cost Sensors in Taiwan

“…A seismic network with closely spaced instruments will deliver these shakemaps precisely, as no interpolation is required. Once five P-Alert instruments record a PGA ≥ 1.5 gal, the network starts plotting shakemaps [36]. These shakemaps are updated at regular intervals after 30 s and are delivered to the intended users, including the National Science and Technology Center for Disaster Reduction (NCDR), for damage assessment and possible rescue operations.…”

“…Yang et al ( 2021) [36] upgraded the NTU network to plot additional PGV, CWB Intensity Scale, and S a shakemaps at different periods as value-added products since 2018. The performance of the system with additional shakemaps was checked using the latest recorded earthquakes in the country.…”

“…Sensors 2021, 21, x FOR PEER REVIEW 7 of 15 shakemaps [36]. These shakemaps are updated at regular intervals after 30 s and are delivered to the intended users, including the National Science and Technology Center for Disaster Reduction (NCDR), for damage assessment and possible rescue operations.…”

Earthquake Early Warning Systems in Taiwan: Current Status

“…The working of this network for EEW and shakemaps plotting during recent damaging earthquakes in Taiwan was explored in some previous studies (Wu et al, 2016(Wu et al, , 2019. Yang et al (2021) improved this network to plot Peak Ground Velocity (PGV), spectral acceleration (S a ), and CWB intensity maps along with PGA maps. By plotting PGA and PGV shakemaps using the denser network of P-Alert instruments, the PGV is supposed to be a better indicator of damage distribution as compared to PGA.…”

Circuit Techniques for High Efficiency Piezoelectric Energy Harvesting

“…The use of piezoelectric energy harvesting technology to convert vibration energy into electrical energy has received extensive attention due to the advantages of high energy density and ease of integration. It can be applied to blood glucose monitor, tumor oxygenator, road monitoring, tire pressure monitoring and other scenarios [4][5][6][7][8][9], as shown in Figure 1. Piezoelectric energy harvester (PEH) generally adopts a mechanical cantilever structure composed of piezoelectric materials such as lead zirconate titanate [10].…”