【摘要】 通过对昌黎台地电场2002—2010年资料整理分析,利用多极距去噪声观测原理在排除了大量噪声后提取到了7组异常信号,其中两组连续两天出现.这些异常信号对应了6次距昌黎台400km范围内发生的ML>4.0地震,异常出现时间一般在发震前约32天以内,说明这些异常是地震电信号的可能性较大.这些异常电信号有以下特征:每组6个测道异常变化极性相同;在各个方向上这些地震电信号均匀度较好,7组信号中每组长、短极距异常幅度ΔV之差76%在1—2mV/km左右.在这7组异常信号中有5组在NE测向上异常幅度最大,2组在NS测向上异常幅度最大,EW测向上异常幅度一般居中或最小.昌黎台所记录到的这7组异常地震电信号表明,异常幅度ΔV与震级M、震中距r之间可能存在着一定的经验关系,即M=lg(ΔV·r)+1.5.更多还原

【Abstract】 We analyzed the geoelectric field data recorded at Changli station from 2002 to 2010, and identified seven sets of abnormal signals after eliminating a lot of noises based on the multi-dipole observation system. The abnormal signals correspond to six ML>4.0 earthquakes that occurred within 400 km from Changli station, and appeared generally within 32 days before the earthquakes, indicating that the abnormal signals are most likely seismic electric signals (SESs). The SESs have the following characteristics: ① each set of the SESs has the same polarity for both long and short dipoles; ② a good uniformity of the signals is found in each direction, e.g., 76% of the ratios of signal amplitudes (ΔV) of long dipoles to those of short dipoles in the same direction are within the range of 1—2. Five of the seven sets of SESs have their largest signal amplitude in NE direction, and two sets have their largest signal amplitude in NS direction. The signal amplitudes in EW direction are smaller than in the other two. The seven sets of SESs recorded at Changli station show that the signal amplitude ΔV is related to earthquake magnitude ML and epicentral distance r as follows: M=lg(ΔV·r)+1.5.更多还原