Preliminary reconnaissance report for the Kashmir earthquake of 8 October 2005

Abstract

A magnitude (Mw) 7.6 earthquake occurred at 8.55 am (local time) on 8 October 2005 causing extensive damage to buildings, bridges and roads and killing in excess of 87,000 people in the Kashmir region of northern Pakistan. Damage and deaths were also reported from Indian Administered Kashmir and eastern Afghanistan. The most severely affected region was in the epicentral area around Muzaffarabad in Pakistan Administered Kashmir. Reverse or thrust fault rupture on or near the Main Boundary Thrust of the Himalayas has been reported or observed from Chennari in the Jhelum River valley upstream of Muzaffarabad through to Muzaffarabad and over into the Kaghan valley as far north as Balakot, a distance of approximately 60 km. A notable feature of the effects of this earthquake was the asymmetric distribution of landslides across the fault rupture zone. On the downthrown or footwall side (to the southwest) landslide damage was relatively minor – the road from Manshera to Muzaffarabad was open to traffic within 8 hours of the earthquake and required the clearance of only one landslide. On the up-thrown or hanging wall side of the fault rupture zone (to the northeast) the road from Balakot to Kagan required the clearance of 253 landslides and took 24 days. These observations are consistent with the findings of recent strong motion studies.

The impact of topography on seismic amplification during the 2005 Kashmir Earthquake

“…According to Kamp et al (2008), bedrock lithology (comprising highly fractured slate, shale, dolomite, limestone and clastic sediments) was the most important landslide controlling parameter during the 2005 Kashmir earthquake. Dellow et al (2007) reported a highly asymmetric size and distribution of 2005 Kashmir earthquake induced landslides. According to this last paper, the landslides can be classified into the following three types: (1) landslides formed over/adjacent to the fault rupture,…”

“…And as mentioned earlier, Shafique et al (2008) compared the aspect of landslides relative to the initial rupture point and found that about 80% of the landslides had an aspect facing away from the rupture point. In summary, the major controlling factors for 2005 Kashmir earthquake induced landslides were (1) human activity (Owen et al, 2008), (2) bedrock lithology (Kamp et al, 2008), (3) proximity with reference to fault trace (Dellow et al, 2007) and (4) slope direction with respect to source (Shafique et al, 2008). In our study, we analyzed landslide aspects with respect to the point of maximum release of energy (CMT solution).…”

Is there a safe spot?

“…According to Kamp et al (2008), bedrock lithology (comprising highly fractured slate, shale, dolomite, limestone and clastic sediments) was the most important landslide controlling parameter during the 2005 Kashmir earthquake. Dellow et al (2007) reported a highly asymmetric size and distribution of 2005 Kashmir earthquake induced landslides. According to this last paper, the landslides can be classified into the following three types: (1) landslides formed over/adjacent to the fault rupture, (2) landslides which extend about 10-20 km from the fault trace on the hanging side of the fault and (3) landslides on the footwall side which are generally rare except within 2-3 km of the fault trace.…”

“…It is considered to be the first Himalayan earthquake that was accompanied by surface rupture, reactivating the Muzaffarabad Fault (MF) (Figure 2.1) and, locally, offsetting the MBT (Hussain et al, 2009). Field investigations (Yeats et al, 2005;Kumahara and Nakata, 2006;Dellow et al, 2007;Kaneda et al, 2008) revealed a surface rupture60-70 km long, with up to 7 m vertical separation, mostly along the pre-existing MF.…”

“…The International Charter "Space and Major Disasters" was activated following the 2005 Kashmir earthquake and high resolution satellite imagery was made available for the Muzaffarabad region. In a reconnaissance study after the 2005 Kashmir earthquake, Dellow et al (2007) found that the epicentral area was the most severely damaged region during the earthquake. Shafique et al (2011b) conducted a detailed field survey following visual interpretation of damage from satellite imagery.…”