Abstract This paper examines downhole measurement inaccuracy with respect to the sampling interval by utilizing theoretical simulation and experimental data collected during the Seismic Microzonation study in Central Italy. Numerical simulation concerning the expected experimental data shows that the percent uncertainty relative to measured P-wave velocity (Vp) values increases with increasing sampling intervals of seismometric measure and Vp values and decreases with depth. In particular, setting Vp = 4000 m/s and by varying the sampling interval in the range (0.125, 0.250, 0.500 ms), the uncertainty reaches 40% at 2 m of depth for dt = 0.50 ms. When dt = 0.125 ms, the uncertainty decreases to 10%. A general equation relating uncertainty on Vp measurements with the actual layer velocity, allowed to derive ambiguity on the first break time, the source-sensor distance and the depth. Experimental data confirmed validity of this equation and put in evidence the effect of measurements sampling interval on the resolving power of DH measurements.

中文翻译：

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意大利中部地震微区带理论模拟和实验数据评估井下地震波速度不确定性

摘要 本文利用在意大利中部地震微带研究期间收集的理论模拟和实验数据，研究了与采样间隔有关的井下测量不准确度。关于预期实验数据的数值模拟表明，相对于测量的 P 波速度 (Vp) 值的百分比不确定性随着地震测量和 Vp 值的采样间隔的增加而增加，并随着深度的增加而减小。特别是，设置 Vp = 4000 m/s 并通过在范围（0.125、0.250、0.500 ms）内改变采样间隔，dt = 0.50 ms 在 2 m 深度处的不确定性达到 40%。当 dt = 0.125 ms 时，不确定性降低到 10%。将 Vp 测量值的不确定性与实际层速度相关联的一般方程，允许推导出第一次中断时间的模糊性，源-传感器距离和深度。实验数据证实了该方程的有效性，并证明了测量采样间隔对 DH 测量分辨率的影响。