Characteristics of late quaternary activity along the Southern Border Fault Zone of Weihe Graben Basin

Characteristics and genetic mechanism of the Cuihua Rock Avalanche triggered by a paleo-earthquake in northwest China

“…Since the Oligocene, when the Weihe Basin (i.e., Guanzhong Plain) began to sink and accept sediment, the activity of the Qinling Piedmont Fault (also known as the northern QL margin fault) along the basin margin had been very strong. Moreover, Zhang et al (1995) reported that the activity of the Qinling Piedmont Fault is outstanding in the Quaternary, especially since human activity began. The vertical differential movement rate of the fault reached 1.7-3.4 mm/a in the Holocene (Li et al, 1992;Peng et al, 1992).…”

“…Qinling in the south, as well as the Weihe Plain (also known as Guanzhong Plain or Weihe Basin) in the north, are the two most east-west-striking geomorphic units. The Northern Qinling Margin Fault (Figure 2) extends eastward for over 310 km from Baoji to Tongguan and is the largest and most intensely active fault in this area (Zhang et al, 1995). The formation lithology in the region of the rock avalanche is mainly composed of migmatitic granite (Tγ 5 1 ).…”

Paleoseismic study on active normal faults in the southeastern Weihe Graben, central China

“…Although the tectonic activity and structural features of active faults in the epicentral area of the Huaxian great earthquake have been reported previously (e.g., Li and Ran, 1983;SSB, 1988;Zhang et al, 1995;Hou et al, 1998;Yuan and Feng, 2010;Rao et al, 2014), the seismogenic behavior of associated faults remains unclear. Based on field observations of fault scarps and outcrops, previous studies have inferred that the Huashan Piedmont Fault (HPF in Fig.…”

Characteristic analysis of large-scale loess landslides: a case study in Baoji City of Loess Plateau of Northwest China

“…1, which triggered numerous landslides in the loess areas (Zhang et al, 1995;Derbyshire et al, 1999;Zhang and Wang, 2007). However, only three earthquakes with around M s = 3.5 have been recorded in Baoji city and its adjacent area.…”

“…The Weihe basin, being a trans-tensional basin, is half-crescent shaped, about 350 km in length from Baoji eastward the Yellow River, and about 30-80 km in width from the Qinling Mountains and the Huashan Mountains northward to the Ordos Plateau. An intensive, uneven vertical movement of a fault zone occurred in the period from the Tertiary to the beginning of the Early Pleistocene, in which the Qinling Mountains and the Ordos Plateau uplifted and the Weihe graben basin was infilled by a 6000-m-thick accumulation of Neogene strata (Zhang et al, 1995). With a further uplift starting at the end of the Pliocene, lacustrine deposits changed from clays to fluvial gravel and sand sequences, and alternating layers of argillites, arenites and conglomerates were laid down.…”