Earthquake is one of the most destructive natural disasters, it can not only cause heavy casualties and economic losses, but also may even lead to serious secondary disasters. As the main bearing body in earthquake, buildings often suffer serious damage, so they can be used as an important reference for post-earthquake disaster loss assessment. Timely and accurate acquisition of regional earthquake damage information after an earthquake is of great significance for scientific and effective emergency rescue and disaster loss assessment. At present, the main methods for earthquake damage identification can be roughly divided into two categories: 1) Manual visual interpretation investigation method. It takes a lot of time for manual field investigation or manual identification of earthquake damage images to process a large amount of seismic damage information in a short period of time, and it is likely to lead to inconsistent discrimination standards for seismic damage of buildings. 2)Image recognition method based on satellite image or UAV image. The recognition method based on satellite remote sensing image after the quake identifies earthquake damage by the texture, brightness and other characteristics of the image of the seriously collapsed buildings, thus, it can quickly get the seismic damage situation in a large area, but as results of offset, low resolution and poor timeliness of the satellite image, it is hard to identify the slightly overlaying and cracking of tiles on the roof of buildings. The combination of high-resolution image obtained by UAV and machine learning algorithm can not only reduce the labor input, but also bring a high accuracy rate. Therefore, based on ant colony algorithm(ACO)and high-resolution remote sensing image of UAV, this paper proposes a new method to efficiently identify the earthquake damage of buildings in the study area, which was applied and verified in the recent Yangbi M6.4 earthquake in Yunnan Province. By improving the update strategy of pheromone concentration in ant colony algorithm and introducing the optimization operator, the better identification rules are established, and the speed and accuracy of earthquake damage identification are enhanced. The UAV high-resolution image of Yangbi county seat was obtained the first time after the Yangbi, Yunnan Province, M6.4 earthquake took place, and taking the image as experimental data, the extraction effect of regional earthquake damage is verified, and compared with ant colony algorithm and maximum likelihood method. The results show that the proposed earthquake damage identification method based on improved ant colony algorithm and UAV high-resolution image can effectively improve the identification accuracy and efficiency of damaged buildings in the region, which is of great significance for post-earthquake emergency rescue and providing accurate disaster information.

The 3^rd Aug 2014 Ludian M_S 6.5 earthquake caused heavy casualties and damages to houses, which is one of the typical phenomena that a small earthquake causing heavy disasters in recent years in Yunnan Province. After the earthquake, a team (including the author) carried out a number of field investigations to the hardest-hit Longtoushan Township. The surveys involved various earthquake disasters, including landslides, ground fissures, fault profiles, building (construction) disasters, and so on. It is found that Longtoushan Township is the most seriously hit area, which locates on the intersection of the NW- and NE-trending faults. The earthquake caused a number of landslides with a predominant distribution in NE direction. The landslides distribution has a good relationship with the NE-trending Zhaotong-Ludian Fault. The ground fissures in the hardest-hit Longtoushan township showed a predominant distribution of NE direction, while the ground fissures in Guangming Village, which locates on the south of Longtoushan township about 6.5km away (Fig. 2), showed a predominant distribution of NW direction.
Meanwhile, a series of NE-, NW-trending fault outcrops, suspected fault scarps and troughs were found, and fissures and small dislocations were generated along these structures. On the basis of the field investigations, and considering the distribution characteristics of aftershock sequences and earthquake isoseismic lines, we infer that the seismogenic structure is the NW-trending Baogunao-Xiaohe Fault. Meanwhile, we could not exclude the tectonic effect of the NE-trending fault, for a large number of geological disasters such as tectonic fissures and landslides were observed along the NE-trending fault. The ground fissures and small dislocations are closely related to the distribution of the faults, which are likely to be a reflection of coseismic surface rupture of this earthquake.

The spatiotemporal distribution of earthquake with M≥6.7 has the characteristics of clustering in Yunnan region in the 20^th century. Since the end of 4^th active period of strong earthquake marked by Lijiang M7.0 earthquake in 1996, the study on initial large earthquake of the active period of strong earthquake in 21^th century has been taken as the keystone for the tracking of seismic situation. On 24^th, March, 2011, the Mong Hpayak M7.2 earthquake occurred in Myanmar, about 80km apart from the border between Yunnan, China and Myanmar. The geodynamics and the ascription of seismic zones of the earthquake have very important influence both on the statistic feature and the further analysis of seismicity with M≥6.7 in Yunnan region. According to the data of the distributions of surface ruptures and aftershocks, the seismogenic structure of Mong Hpayak earthquake is the NE-trending Nam Ma Fault which passes through the border between Yunnan and Myanmar. Meanwhile, there are a series of parallel distributed NE-trending active faults including Nam Ma Fault in the region from the northern Tengchong, Longling in Yunnan, to the southern border area among Myanmar, Laos and Thailand, most of these faults are active during Holoscene and had generated earthquakes with M≥7 in history. These M≥7 earthquakes, together with many other smaller earthquakes, form a NNW-direction dense seismic belt across Yunnan, Myanmar, Thailand and Laos. Our comprehensive studies on the regional tectonic evolution, contemporary crust movement state and seismicity have proposed that the Mong Hpayak M7.2 earthquake has the same geodynamic source as that of those earthquakes in southwestern Yunnan region. Moreover, the seismogenic structure of Mong Hpayak M7.2 earthquake connects with those earthquakes in SW Yunnan. Therefore, all the earthquakes mentioned above should be taken as in the same seismic belt and be brought into the statistic analysis of seismicity features in Yunnan region. It implies that the Mong Hpayak M7.2 earthquake is prologue to the active period of strong earthquake in 21^th century in Yunnan region, and the seismic risk level in the region of eastern Red River Fault may be higher than that in the western region according to the statistic study.

Analyses based on investigation of the seismic intensity and digital seismic data by mobile observation on-site from the Yao'an M6.0 Earthquake that occurred on 9th July 2009 in Yao'an county,Yunnan Province,and on the spatial distribution of earthquake sequences,focal mechanisms,and intensity distribution of other three earthquakes that occurred since 2000 in the same area with the similar magnitude,show that there are obviously different characteristics in earthquake focal depth,direction of the long axis of isoseismal lines,major trend of sequence spatial distribution,and so on of the four earthquakes. Comprehensive analyses combined with data from petroleum seismic exploration show that the regional seismotectonic setting is very complicated,featured by seismotectonics interweaved with different strikes and faulted structures coupling at different depths in Yao'an area.

Correlated evidences about the newest activity of Red River Fault in Vietnam(RRFV),such as seismicity,geology,geomorphology and chronology etc,have been obtained through joint survey along the fault in Vietnam. Our comprehensive studies demonstrate that,the same tendency of gradual weakening of the fault activity from north to south in the part of China since Quaternary has been kept on in Vietnam. The primary active period of Red River Fault in Vietnam is in late of middle Pleistocene,and in general,the active level of Red River Fault is lower prominently than that in Yunnan,China,especially,the activity of RRFV has been very weak since late Pleistocene. The synthesized analysis on seismicity and regional GPS deformation monitoring data indicates that the dynamic impact of so-called lateral extrusion from Tibetan Plateau on the dextral slip of RRFV should be very limited. Furthermore,the possible reasons including geotectonic and deep crustal structure have been discussed in the article.