Co-seismic changes of well water level and volume strain meter in capital area and its vicinity,due to the Nov.14,2001 Ms8.1 Kunlun Mountain earthquake,China

The Kunlunshan Mountain Ms8.1 earthquake, occurred in Nov.14, 2001, is the first event with magnitude more than 8 in the China earthquake monitoring history, specifically at the beginning of digital techniques in precursor monitoring networks. Any investigation of recorded data on this earthquake is very important for testing the operation of the digital monitoring networks and understanding the preparation, occurrence, and adjustment of stress/strain of strong continental earthquakes. In this paper we investigated the coseismic response changes of well water level of groundwater and volume strain meter of bore hole in digital earthquake monitoring network of Capital area and its vicinity, due to the Nov.14, 2001 Ms8.1 Kunlun Mountain earthquake. The responding time, shapes or manners, amplitudes, and lasting time of well water level and strain-meters to seismic wave are studied in comparison. Then we discussed the possibility that the response changes of groundwater to strong distant earthquakes can be understood as one kind of observing evidence of stress/strain changes induced by distant earthquake.

Earthquake-controlling Processes of Detachment Zones in Eastern North China

The basin-and-range area in eastern North China is known for frequent occurrence of earthquakes, their great magnitudes and heavy losses thereby incurred. Seismic studies in the past usually emphasized the intersections, inflexions and branches of the faults. However, the intensities of many great earthquakes in this area do not show linear distribution, and the epicenters are horizontally dispersed at certain depths instead of along the strike of faults. Based on the sub-mantle plume studies made by authors in the past decade, it is thought that there exists an uplifted sub-mantle plume under the fault depression area in North China. The uplifting and intrusion of mantle materials caused the upper crust to be faulted, while low-velocity and high-velocity layers are alternatively distributed in the middle crust under the influence of the mantle and the lower crust. The middle and lower crust materials were detached from the top of the sub-mantle plume to the surroundings while the sub-mantle plume materials were detached outward. When the detached middle and lower crust come to the boundary of fault basins in the upper crust, they will be obstructed by the orogenic zone and the detachment will go slower. The shearing between them will cause the stress to accumulate and release alternatively, so that earthquakes occurred frequently in the areas of sub-mantle plume and its surroundings.

Habitat restoration is the greatest challenge for population recovery of Hainan gibbons(Nomascus hainanus)

Hainan gibbons are among the world’s most critically endangered primates,with a remaining population of only 35 individuals distributed across 5 social groups in the Bawangling Branch of the Hainan Tropical Rainforest National Park,China.Habitat conversion and forest fragmentation over the past 40 years have reduced their geographical distribution by 95%.In the absence of a quantitative assessment of the availability of remaining suitable habitat,it is unclear whether this species can survive to the end of this century.We used behavioral observations,ArcGIS,remote sensing,stereo optical imagery,and MaxEnt modeling to identify patterns of Hainan gibbon range use and compare changes in the distribution of suitable forest types and areas of forest fragmentation over the past 20 years(2000–2020).The results indicate that the combined range of the 5 extant Hainan gibbon groups totaled 14.89 km2.The home range of the smallest group(Group E,3 individuals)was 1.51 km2,which likely represents the minimum home range size for this species.The remaining area of highly suitable and moderately suitable habitat totals 26.9 km2.However,habitat connectivity across the gibbon range is very low(less than 0.5),limiting the ability of Hainan gibbons to move between forest patches.The results of this study indicate that the availability of suitable habitat in Bawangling is insufficient to allow for future Hainan gibbon population growth.Therefore,immediate action must be taken to restore,reforest,and establish ecological corridors to reconnect areas of suitable habitat for these critically endangered gibbons.