Seismic quiescence precursory to a past and a future Kurile island earthquake
Seismic quiescence precursory to a past and a future Kurile island earthquake
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地震静止是过去和未来千岛岛地震的前兆
DOI：
10.1007/bf00876215
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发表时间：
1979
期刊：
影响因子：
--
通讯作者：
R. E. Habermann
中科院分区：
文献类型：
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作者：
M. Wyss;R. E. Habermann
本文通过对1960年至1978年初千岛岛弧45° ~ 53°N段11个半径为100 km的重叠体内浅源（h≤100 km）地震累积活动性的研究，系统地探讨了该区地震活动率的变化。我们发现，在这个岛弧的大部分地区和大部分时间的地震活动率，从NOAA目录中获得的，不排除任何事件是相当恒定的，除了在20世纪60年代中期增加的地震活动在南部部分由于1963年的大主震，和地震活动的平静在研究的时间段内的两个明确的部分弧。其中第一个是1973年（Ms=7.3）主震周围半径为100 km的体积，其中地震活动率在99%置信水平下被证明在主震前2100天（5.75年）内降低了50%。第二个地震平静区与400公里长的北千岛湖空区相吻合。与1967年以前的差距内地震活动率以及差距周围的地震活动率相比，该缺口内的地震活动率（在99%置信水平下）从1967年至今（1978年）降低了50%。我们认为，千岛湖空区异常低的地震活动率是一个大地震的前兆，其发生时间可由地震平静时间与震源维数T = 190 L ~（0.545）的初步关系式来估计。我们预测，从现在到1994年，沿北千岛岛弧（北纬45.5° ~ 49.2°）沿着将发生震源长度为200-400 km（M>8）的地震。
A systematic search was made for seismicity rate changes in the segment of the Kurile island arc from 45°N to 53°N by studying the cumulative seismicity of shallow (h≤100 km) earthquakes within 11 overlapping volumes of radius 100 km for the time period 1960 through beginning of 1978. We found that in most parts of this island arc and most of the time the seismicity rate as obtained from the NOAA catalogue and not excluding any events is fairly constant except for increased seismicity in the mid 1960s in the southern portion due to the great 1963 mainshock there, and for seismicity quiescence during part of the time period studied within two well defined sections of the arc. The first of these is a volume of 100 km radius around a 1973 (Ms=7.3) mainshock within which the seismicity rate was demonstrated at the 99% confidence level to have been lower by 50% during 2100 days (5.75 years) before this mainshock. The second volume of seismic quiescence coincides with the 400 km long north Kuriles gap. In this gap the seismicity rate is shown (at the 99% confidence level) to be lower by 50% from 1967 to present (1978), in comparison with the rate within the gap befor 1967, as well as with the rate surrounding the gap. We propose that the anomalously low seismicity rate within the Kuriles gap is a precursor to a great earthquake, the occurrence time of which was estimated by the following preliminary relation between precursory quiescence time and source dimensionT=190L0.545. We predict that an earthquake with source length of 200–400 km (M>8) will occur along the north Kurile island arc between latitude 45.5°N and 49.2°N at a time between now and 1994.