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1983年作者在昆明举行的南北地震带会议上提出了立交模式。1985年正式发表(本刊)。本文是上一篇文章的继续,重点讨论了以下的问题。1.把立交模式应用于解释远距离的大震迁移,具体讨论了横穿青藏高原和鄂尔多斯地台的大震短期迁移现象。这种远距离跨越大地构造单元的震中迁移已往是很难理解的,但是从立交模式来看,则是很自然的。2.由于下岩石圈近于塑性,且相对均匀,所以在大区域构造压力作用下,其内形成的剪切滑移线与区域压力成45°角,因之如果己知若干地震排成一条线则可认为与其相交45°角的方向就是主压应力方向,这可与震源机制所求得的P轴方向相互补证。依此方法对华南和甘青地区的主压应力方向作了推求。3.在用相距较远的地震连直线的时候,对于中等强度的地震至少得三个地震连直线,对大震来说,两个即可。这是因为大震的断层面通入地下深,直接受到下岩石圈中蠕滑断层的影响。而中等强度的地震的震源断层面如插入地下浅时,则不直接受这个蠕滑断层的影响,因之取两震连线难排除偶然性。如三震相连则可能是深部蠕滑断层共同制约,不然为何在短时间电它们连成一条线。4.如果已知区域主压应力方向(用一些大震震源机制所求P轴方向的平均或用其他方法求得),则当一处发生大震后,可通过震中作与主压应力方向成45°夹角的直线,此直线即为今后震中迁移的较可能的方向,这个直线有时与已发地震的断层走向一致。5.一些外因,如固体潮和极移等有可能影响下岩石圈中蠕滑断层的动态,並由此影响上岩石圈中大震的发生。这是调制模式的另一种形式,即外因对震源的间接调制。6.我国震中迁移的事实表明,历史上短期震中迁移的始发地区可能是一个前兆穴位。在该区选择良好观测台址进行前兆观测可监视较大范围内的大震发生,特别是监视历史上震中迁移方向上今后再发生的大震。
In 1983, the author proposed the mode of interchange at the North-South Seismic Belt Conference held in Kunming. Officially published in 1985 (magazine). This article is the continuation of the previous article, focusing on the following issues. 1. Applying the overpass model to explain the migration of large earthquakes over long distances, we discuss the short-term migration of large earthquakes across the Qinghai-Tibet Plateau and Erdos platform in detail. The epicenter migration of this long-range transgressive tectonic unit has been hard to understand in the past, but it is quite natural from the perspective of interchange mode. 2. Because the lower lithosphere is near plasticity and relatively uniform, the shear slip line formed within the large regional tectonic pressure is at a 45 ° angle to the area pressure, so if one knows a few earthquakes The direction of principal compressive stress can be considered as the direction of intersecting 45 ° with the line, which can complement each other with the P-axis direction obtained by focal mechanism. According to this method, the direction of principal compressive stress in South China and Gansu is deduced. 3. When using the seismic line with a long distance, at least three earthquakes should be straight for medium-intensity earthquakes and two for large earthquakes. This is because the fault plane of a large earthquake leads to deep underground and is directly affected by the creeping faults in the lower lithosphere. The moderate-intensity earthquake focal fault surface, such as inserted into the shallow ground, is not directly affected by the creeping fault, so take two earthquakes hard to exclude by chance. If the three earthquakes are connected, the deep creep faults may be constrained by common faults, otherwise they are connected in a line in a short time. 4. If the direction of the principal compressive stress in the region is known (using the averaging of the P-axis direction obtained by some large-earthquakes source mechanism or by other methods), after a large earthquake occurs, the direction of the principal compressive stress A straight line at an angle of 45 °. This straight line is the more likely direction for future earthquakes to migrate, and this line may sometimes coincide with the strike of an earthquake that has occurred. 5. Some external factors, such as solid tides and polar displacements, may affect the dynamics of creep and slip faults in the lithosphere and thus affect the occurrence of major earthquakes in the lithosphere. This is another form of modulation, which is indirect modulation of the source by external sources. 6. The fact that the epicenter of the epicenter of China was migrating shows that the origin of the epicenter of the short-term epicenter of the earthquake may be a precursor. The selection of good observation sites in this area for precursor observation can monitor the occurrence of major earthquakes over a large area, especially for the monitoring of major earthquakes occurring in the future in the history of epicentral migration.