Seismic potential and neotectonic studies at Karachi, Gadap and Hub areas, southern Kirthar Fold Belt, Pakistan

Abstract

The dream of accurate and reliable earthquake prediction has not yet come true; however, state-of-the-art knowledge enables humanity to at least recognize earthquake-prone areas. In this regard, neotectonic studies have been conducted in the Karachi, Gadap, and Hub areas to locate earthquake environmental effects (EEE) and to assess the seismic potential. Possible active faults manifestation were studied in the recent sediments to understand the intensity of seismic activity. Southern Pakistan has experienced some major and strong earthquakes in the past such as the Makran-1945, Anjar-1956, Bhuj-2001, and Awaran-2013 with magnitude 7.0 – 7.7Mw. However, only ground shaking was observed in the southern inner part of the Karachi Arc area and no EEEs such as neotectonic deformation features, surface ruptures, and liquefaction were observed during the major and strong earthquakes caused by the distant seismogenic sources. The lithological studies of the Quaternary sediments exposed in the Karachi, Gadap, and Hub areas have not revealed the existence of any distortion, offset in the sedimentary strata, paleo-liquefaction, and fault propagation. It indicates the absence of seismogenic sources and no strong or major earthquakes have been occurring in this area in the Quaternary time except a few minor to light (magnitude: 3-4.9Mw) crustal-scale earthquakes.