Statistical Characteristics of Moderate and Strong Earthquake Sequence in Yunnan

The statistical characteristics of 108 moderate and strong M≥5.0 earthquake sequences in Yunnan province is analyzed including the sequence type, the magnitudes, the distribution range, the time interval, and the relationship between the main shock and the aftershocks. The results show that in Yunnan area, earthquake sequence of isolation type, the main shock and after shock type, and multi-shock type accounts for about 3.7%, 63.0% and 3.7% respectively; to the earthquake sequences with main shock M≥5.0, the magnitude of their aftershocks is positively correlated with the magnitude of their main shock. If the main shock is 5.0≤M < 6.5, the maximum aftershocks are in the range of 0-20 km from the epicenter of the main shock; if the main shock is M≥5.0, the maximum aftershocks are in the range of 5-40 km. of all the maximum aftershocks, 68% occurs within 10 days after its main shock, 84% occurs within 30 days, 97% occurs within 90 days. To main shock and aftershock type earthquake sequence and multi-shock type earthquake sequence, the distribution of time interval and epicenter distance between the maximum aftershock and second maximum aftershock are basically the same.