华北—东北地区震磁异常与日本强震对应关系

选取2009—2014年华北—东北地区发生的12次中等地震,对该区8个地磁台站记录的地磁Z分量日变幅进行小波分析及合成计算,与日本海沟同期发生的12次M≥6.5强震进行关联性分析,发现日本强震对中国华北—东北地区中等地震活动具有连带作用,表现在:①日本强震发生前后,华北或东北地区均有M4—5地震出现,频次一般为1—3,间隔几天至5个月左右;②2011年3月10日日本M9.1地震后,华北、东北地区中等地震震级有所升高,其中东北地区由M4升至M5,距日本最近的中俄交界甚至出现M6.1地震,华北地区唐山老震区出现1次M4.8地震,震级接近5;③每次日本强震出现后几天至2个月内,8个地磁台地磁Z分量小波细节6阶合成曲线值均出现2—6个月高值异常,但幅度大小与强震震级无明显规律可循,而华北或东北地区中等地震一般在异常高值出现前后低值附近发生。

Relationship between magnetic anomalies in North China and Northeast China and strong earthquakes in Japan

At frst, 12 moderate earthquakes occurred in north-northeast China from 2009 to 2014 is selected. The wavelet amplitude of the geomagnetic Z component from the 8 geomagnetic stations on this area is recorded. Besides 12 earthquakes with M ≥ 6.5 in Japan Trenches during the same time is found that the strong earthquakes in Japan had a collateral effect on the medium earthquakes in north-northeast China. It is shown that as follows:① Before and after the strong earthquake in Japan, there are 1-3 earthquakes with M 4-5 during a few days to about 5 months in North-Northeast China; ② After the M 9.0 earthquake on March 10, 2011 in Japan, the moderate earthquakes from M 4 to M 5 in North China and Northeast China will increased. Even the M 6.1 earthquake occurred in the Sino-Russian border closest to Japan. At the same time, the M 4.8 near magnitude of 5 occurred in Tangshan old earthquake area; ③ When the strong earthquake in Japan occurred within a few days to 2 months, wavelet detail 6-order arithmetic average synthesis value of the Z component of the 8 geomagnetic stations all showed anomaly with high values for 2-6 months, but the amplitude and intensity of earthquake magnitude did not show any obvious pattern, while the moderate earthquakes usually occurred around anomaly with low values in North China or Northeast China.