Strong-motions from 79 moderate magnitude (5.9 ≥ Mw) earthquakes that caused various degrees of impact on humans and built-environment in Japan between 1996 and 2019, after the start of K-NET and KiK-net, are presented. As such, most of the earthquakes occurred beneath the land, and agencies had reported damages from events as small as Mw 4.1. Together, large peak ground accelerations exceeding 500 cm/s² were recorded during 15 earthquakes, reaching approximately 1128 cm/s² during one event. Similarly, large peak ground velocities exceeding 30 cm/s were recorded during ten earthquakes, reaching about 76 cm/s to the maximum. Most of the large values aforementioned were recorded within a hypocentral distance of approximately 30 km and on soil site conditions. Intermediate to long-period ground motions are of growing concerns in urban areas located on sedimentary basins with mid-rise and high-rise buildings. The threshold magnitude for the large ground motions at the periods of about 2–5 s is not well understood. In March 2013, the Japan Meteorological Agency introduced four levels of long-period ground motion intensity (LPGMI) based on absolute velocity response spectra (AVRS) between 1.6 and 7.8 s. In the present data set, LPGMI of level 3 (AVRS 50–100 cm/s) and level 4 (AVRS >100 cm/s) were observed each at a single site from shallow-focus earthquakes of Mw 5.8 and 5.9 at distances of approximately 12 and 15 km, respectively. However, the peak response periods were relatively short (1.6–1.8 s). The data showed that LPGM from moderate earthquakes is of lower concern regarding earthquake early warning at distances beyond 200 km. The 2018 Mw 5.5 North Osaka earthquake, despite the moderate magnitude, caused the loss of six human lives and brought significant damage to buildings and lifelines. Comparing the data with the ground motion prediction equations (GMPEs) and other events suggested that the North Osaka earthquake was probably a higher stress drop event. These moderate earthquakes’ observations hinted that the commonly used GMPEs in Japan may not sufficiently grasp these earthquakes' hazards.

介绍了在K-NET和KiK-net开始之后的1996年至2019年间，日本发生了79次中度（5.9 MW）地震，这些地震对日本的人类和建筑环境造成了不同程度的影响。因此，大部分地震都发生在陆地以下，而各机构报告说，地震造成的损害小至Mw 4.1。在一起，在15次地震中记录到的最大峰值地面加速度超过500 cm / s ²，达到约1128 cm / s ²在一次活动中。同样，在十次地震中记录到的最高峰值地速超过30 cm / s，最大达到约76 cm / s。上面提到的大多数大数值都记录在大约30 km的震中距离内以及土壤现场条件下。在具有中层和高层建筑物的沉积盆地上的城市地区，中长期到地下的运动越来越引起人们的关注。大约2到5 s的周期内大地面运动的阈值幅度还不太清楚。2013年3月，日本气象厅根据1.6至7.8 s之间的绝对速度响应谱（AVRS）引入了四种水平的长期地面运动强度（LPGMI）。在当前数据集中，LPGMI为3级（AVRS 50–100 cm / s）和4级（AVRS> 在大约5.8 km和5.9 mw的浅焦点地震中，分别在大约12 km和15 km的距离处的一个站点观测到100 cm / s）。但是，峰值响应时间相对较短（1.6-1.8 s）。数据表明，对于200公里以上的地震早期预警，中度地震的LPGM引起的关注较少。尽管中度震级，2018年的北大阪Mw 5.5地震造成6人丧生，并对建筑物和生命线造成重大破坏。将数据与地面运动预测方程（GMPEs）和其他事件进行比较表明，北大阪地震可能是一个较高的应力下降事件。这些中等地震的观察结果表明，日本常用的GMPE可能无法充分把握这些地震的危害。