ZHANG Fan, senior engineer, majors in earthquake prediction methods, E-mail: spacelessness@163.com
We investigate the crustal stress field in Inner Mongolia using 728 focal mechanism solutions and 14 460 P-wave polarity data derived from 2 793 earthquakes based on three different strategies. The Inner Mongolia area is divided into 1°×1° grids, and three methods are applied: a composite focal mechanism solution method based on first-motion polarity data, a Bayesian right trihedra method(BRTM) based on focal mechanisms, and a weighted fusion method of polarity and focal mechanism data. The results from polarity-based and focal mechanism-based methods show good consistency. The abundance of polarity data, compared to limited focal mechanism data, enables stress inversion in a wider spatial extent. After weighted fusion of polarity-based results with focal mechanism data, the BRTM successfully obtains stress results at 125 grid points, expanding the coverage and reducing uncertainties. The study reveals significant spatial variations in the stress field across Inner Mongolia area. The eastern regions are dominated by shear and extension, with shearing concentrated along the Daxinganling and extension characterizing the basins on both sides. Localized compression is observed near Chifeng and Tongliao in the southeast. The northern margin of Ordos block exhibits extension characteristics, while the Alxa block displays shear features. The orientations of maximum principal stress exhibit considerable differences, while the minimum principal stress directions remain relatively uniform.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |