SUMMARY

Faulting segmentation for estimation of maximum earthquake in Việt Nam

Cao Đình Triều, Nguyễn Đức Vinh

On the basis of a combination of data derived from the analysis of geological, geophysical and topographical parameters obtained from the M 6.7 Tuần Giáo 1983 earthquake rupture zone and compared with currently available data, this study revealed a number of indicators which can be used to identify the segmentation of active fault zones that can be used for prediction of maximum earthquake magnitude. Major results are as follows:

1. The fault segments used for estimation of maximum earthquake shall be a major tectonic break separating crustal blocks of different composition and physical properties; zones separating the gravity and magnetic anomalies; suddenly changing the thickness and spatial distribution of crustal layers; abrupt change of thickness of sedimentary units, especially modern sedimentary sequences; visible topographic lineaments on modern topography, satellite images, or DEM maps; formation of special morphological features or controlling the formation and morphology of valleys and modern or Quarternary basins, occurrence of earthquake, exposure of thermal or mineral water, landslides and other neotectonic events and other recent tectonic deformation.

2. Two following formulas on the correlation between the length of fault and maximum earthquake proposed by Cao Đình Triều (2004): log L (km) = 0.6 Ms – 2.5 and Wells and Copersmith (1994): M = 4,38 + 1,49 log L for estimation of maximum earthquake in Việt Nam.

Người biên tập: PGS.TS Trần Thanh Hải.