South Korea has implemented borehole-type seismometers for reliable earthquake observations and earthquake early-warning systems, with approximately 85% of seismometers being replaced by borehole-type seismometers after the Gyeongju earthquake. Although these seismometers are more effective at detecting earthquakes owing to the reduced artificial ambient noise, they do not record surface-level shaking. Therefore, it is necessary to estimate ground surface shaking directly associated with potential damage when using borehole-type seismometers without surface sensors. This study investigated and compared various methods, including the stochastic point-source ground-motion model, transfer function based on ambient noise, and one-dimensional site response, to estimate horizontal seismograms of the ground surface. We assessed the accuracy of these methods by comparing the waveforms generated in event cases (magnitude from 2.5 to 5.8, with epicentral distances spanning 22 km–209 km) in terms of Fourier spectra, intensity, and spectral acceleration. Among the methods assessed, the transfer function approach, which does not account for the geophysical characteristics such as , proved to be the most appropriate for correcting ground-surface effects.

中文翻译：

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一种利用钻孔地震仪预测地表强运动的方法

韩国已采用钻孔式地震仪来实现可靠的地震观测和地震预警系统，庆州地震后约 85% 的地震仪被钻孔式地震仪取代。尽管由于人工环境噪声减少，这些地震仪在检测地震方面更加有效，但它们不会记录地表震动。因此，在使用不带表面传感器的钻孔式地震仪时，有必要估计与潜在损害直接相关的地表震动。本研究研究并比较了各种方法，包括随机点源地震动模型、基于环境噪声的传递函数和一维场地响应，以估计地表水平地震图。我们通过比较事件案例（震级从 2.5 到 5.8，震中距离跨越 22 km-209 km）生成的波形的傅里叶谱、强度和谱加速度来评估这些方法的准确性。在评估的方法中，传递函数方法没有考虑地球物理特征，例如 ，被证明是最适合校正地表效应的方法。