A magnitude 7(3/4) earthquake happened in Linfen, Shanxi, on May 18, 1965(the 34th year of Qing Emperor Kangxi). In the Catalogue of Chinese Historical Strong Earthquakes, the epicenter of this earthquake is located at the northwest of Zhangli Village of Xiangfen County and Dongkang Village of Yaodu District, Linfen City(36.0°N, 111.5°E), and the epicentral intensity is Ⅹ. It was inferred by previous studies that Guojiazhuang Fault is the seismogenic structure of the earthquake. In this paper, in cooperation with the Archives of Linfen City and Earthquake Administration of Linfen, the author looked up in details the first-hand materials of the earthquake damage to the ancient town of Linfen and its surrounding areas, and based on this, drew the isoseismals of the earthquake. Through discussions with relevant experts, we consider that it would be more appropriate that the location of the macroscopic epicenter of this earthquake is in Donguan area of the ancient town of Linfen, the epicentral intensity is Ⅺ, and the major axis of the isoseismals is in NWW. Later, in the implementation of "Linfen city active fault detection and seismic risk evaluation", we found two earthquake fault outcrops near the macroscopic epicentral area of the 1695 Linfen earthquake. Shallow seismic exploration lines and drill rows perpendicular to the strike of the fault outcrops were arranged to implement the exploration. The results demonstrate that the right-lateral stepover composed of Guojiazhuang Fault and Liucun Fault, together with the Luoyunshan Fault(Longci segment), were involved in the 1695 Linfen earthquake, the intersection of the faults is the microscopic epicenter of the earthquake, and the above-mentioned three faults are the seismogenic structure of the earthquake. In addition, the seismic geological remains in this region(landslides, earthquake ground cracks, sand emitting channels, etc.) are mainly distributed on the hanging wall of the Guojiazhuang Fault, this proves from another perspective that the earthquake remains is the product of activity of Guojiazhuang Fault in 1695.

Based on the 1︰50000 geological and geomorphologic mapping of active fault, the structural geomorphic features and activity of Hancheng Fault are investigated in detail. In the study, we divide the fault into three sections from north to south: the section between Xiweikou and Panhe River, the section between Panhe River and Xingjiabao and the section between Xingjiabao and Yijing, the three sections show different characters of tectonic landform. The section between Xiweikou and Panhe River is a kind of typical basin-mountain landform, where diluvial fans spread widely. In the north of Yumenkou, the fault deforms the diluvial fans, forming scarps, along which the fault extends. In the south of Yumenkou, the fault extends along the rear edge of the diluvial fans. In the section between Panhe River and Xingjiabao the fault extends along the front of the loess mesa. In the section between Xingjiabao and Yijing the fault forms scarp in the loess and extends as an arc shaped zone, and the landform is formed by the accumulative deformation of the fault. The activity of the fault becomes weak gradually from northeast to southwest. The fault activity of the section between Xiweikou and Panhe River is the strongest, and the latest age of activity is Holocene. The slip rate since the mid-Holocene is bigger than 0.8mm/a at Yumenkou. The fault activity of the section between Panhe River and Xingjiabao is weaker than the north part, the fault's latest active age is identified as the later period of Late Pleistocene and the activity becomes weak gradually from northeast to southwest. At the estuary of the Jushui River the slip rate of the fault is about 0.49mm/a since late Late Pleistocene. The fault activity of the section between Xingjiabao and Yijing is the weakest. There is no evidence of paleosol S1 deformed in fault profiles, and only some phenomena of fracture and sand liquefaction in the earlier Late Pleistocene loess. The activity of the fault is in line with the fault landform feature. At macro level, the relationship between the uplifted side and the thrown side of the fault switches gradually from the Ordos uplifting region and the rifted basin to the interior blocks of the rifted basin, which maybe is the regional reason why the activity of the Hancheng Fault becomes weak from the northeast to the southwest.

On the basis of consulting historical records about the positions of Hukou waterfall at different times,we conduct a field geological survey along the Yellow River and ultimately determine the specific locations of the Hukou waterfall in the different periods.Based on this,the retrogressive erosion rates in different periods are calculated as about 1.66m/year during the Xia Dynasty to the Tang Dynasty period,about 1.01m/year in the Tang Dynasty to the Yuan Dynasty,about 0.97m/year in the Yuan Dynasty to the Ming Dynasty,about 1.28m/year in the Ming Dynasty to the Republican period,and 0.6m/year from the Republican period to the present.Considering the complex geological conditions along the Yellow River,the average retrogressive erosion rate of Hukou waterfall on the Yellow River is obtained to be 1.51m/year since the historical records (early Qin Dynasty to the present).Lithology surrounding the Hukou waterfall includes mainly the Triassic gray,gray-green thick-layered mid-grained feldspar sandstone and dark purple,yellow-green mudstone,this hardness and softness combination feature is the unique geological condition of the Yellow River.After abrasing the softer shale driven by water cyclotron at this position,water washes off the debris,causing the overlying feldspar sandstone suspended for a long period.Feldspar greywacke block collapses under accumulative water erosion in long years,and then retrogressive erosion occurs in Hukou waterfall.In the process of 1 ︰ 50 000 active fault mapping of Hancheng Fault,we excavated a trench at Shaojialing,and the trench profile shows that:in the early and middle period of late Pleistocene,there are obvious surface ruptures produced by the fault.Cumulative offset near the trench is more than 20 meters in height difference.Yellow River terraces survey at Yumenkou also confirms that a fault slip of about 20 meters occurred during the early and middle period of the late Pleistocene.Assuming the retrogressive erosion rate is constant,the author thinks the Hancheng Fault was activated at early and middle age of the Late Pleistocene,forming a 20~30m high scarp (knick point),and today's position of Hukou waterfall may be the position of this knick point after the retrogressive erosion of about 40 to 50ka.

To study the activity feature, phase and time of the faults in a bedrock exposing region, a series of samples of fault rocks and fault gouges are collected along the Kangding-Moxi fault segment. TL. ESR. K-Ar techniques,analyses of quartz surface texture and deformation microstructure are used for the comprehensive research. The results show that the fault segment has undergone multiperiodic activity with multiple types (ductile shearing-brittle fracture) and multiple patterns (left-lateral-right-lateral),and the lower limit of the lost strong activity was around the end of late pleistocene or the begining of Holocene (ca. 10000 years).

The use of optical pyrometer to measure temperature in diamond-anvil ultrahigh pressure device is different from that under normal conditions because the temperature is measured through the optical system of microscope.Therefore,a caribration is recessary for the used optical pyrometer.There exists an interference from miscellaneous light in using the ruby R₁ fluorescence technique to measure the pressure.In this paper,we introduce a method of temperature calibration for optical pyrometer and discuss how to estimate the pressure in the region of interference.