Morphotectonics of the Lo River fault near Tam Dao (northern Vietnam) : an attempt at seismic prognosis

The Lo River Fault near Tam Dao, northern Vietnam, is a young right-lateral normal fault that has been active throughout the Quaternary. The rates of dextral slip range from 1 to 2 mm/yr, whereas those of uplift can be estimated roughly at 0.1-1 mm/yr. The drainage deflection and arrangement of shutter ridges suggest 1.5-2.0 km of dextral offset during the past 1-2 m.y., and the height of the youngest faceted spurs averages at 170 m. The analysis o f morphometric parameters of the mountain front at Tam Dao indicates that this segment shows properties typical for nearly rectilinear, young normal scarps that belong to class I or II of relative tectonic activity and that are capable of generating potentially strong earthquakes in the future.