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在约二千个弱震资料的基础上,本文首先进行了多台平均波速比的分析,其中采用了人机联合采样的方法。中强震之前,存在着短期趋势,禄劝六级地震之前,似乎还有至少三年的长趋势,这与地震活动性空区的存在是一致的。进一步用机器对地震参数作修订后表明,(1)波速比随深度分层变化;(2)地震的深度分布与中强震发生有相关性。于是作波速比的分层分析,并认为至少对本文讨论的地区,浅层弱震资料提供震前波速比异常有困难;中层(16Km≥h>7Km)震前波速比的降低对禄劝地震达3.5%,深层在临震前的波速比回升上比中、浅层都清楚。为此,本文在地下 h=7公里的截面上,更清晰地得到了以单台资料为基础的波速比平面分布情况。禄劝地震以前显示了二个特点,一是震前某一个时期,围绕空区,异常点明显增多,二是临震之前,空区附近出现高值后,而外围却保留着一些异常点,或称之高值围空。接着,本文对上述 h=7公里处的 r_0分布作二次曲面模拟,定量分析的结果与定性分析的结果,吻合良好。最后,作了简要讨论。提出把空区与波速变化结合起来讨论的建议。
Based on the data of about two thousand weak earthquakes, this paper first analyzes the average wave velocity ratios of multiple stations, and adopts the method of human-machine joint sampling. Before the moderate strong earthquakes, there was a short-term trend. Before Lu urged the M6 earthquake, there seems to be a long-term trend of at least three years, which is consistent with the existence of the seismicity airspace. Further revision of the seismic parameters using the machine shows that: (1) the velocity ratio varies with depth; (2) the depth distribution of the earthquakes correlates with the occurrence of moderately strong earthquakes. Therefore, the stratigraphic analysis of the wave velocity ratio shows that it is difficult to provide the anomalous wave velocity anomalies before the earthquake for at least the shallow seismic data discussed in this paper. The reduction of the wave velocity ratio before the earthquake in the middle layer (16 km × h> 7 km) 3.5%. The wave velocity ratio of the deep before the quake was higher than that of the middle and the shallow layers. Therefore, in this paper, the distribution of wave velocity ratio plane based on single data is more clearly obtained on the cross section of 7 km underground. Before the Earthquake, Luquan showed two characteristics. One was around some time before the earthquake, and the anomalous point was obviously increased around the quake. Before the quake, there was a high value near the vacant area while some abnormal spots were kept on the periphery. Or called the high value of the air. Then, the paper simulates the r_0 distribution at h = 7 km above, and the result of quantitative analysis is in good agreement with the result of qualitative analysis. Finally, a brief discussion. Propose to discuss the change of empty space and wave velocity.