Poor superstructure maintenance led to collapse of Valley monuments: Study

Poor superstructure maintenance led to collapse of Valley monuments: Study

A collaborative team of international and national experts from the Department of Archaeology and Durham University, UK undertook a series of post-disaster surveys and rescue excavations of earthquake damaged UNESCO World Heritage monuments in Kathmandu Valley from October 5 till November 22.

The earthquake of April 25 and its associated aftershocks not only claimed around 9,000 lives but also generated a cultural catastrophe, damaging and destroying much of Nepal’s unique cultural heritage, including monuments within the UNESCO Kathmandu Valley World Heritage Site of Universal Outstanding Value.

In response, national experts from the DoA, in collaboration with archaeologists from DU, undertook a series of archaeological investigations, including surveys and excavations in the three earthquake damaged Durbar Squares of Hanumandhoka, Patan and Bhaktapur.

The project was directed by Kosh Prasad Acharya, former director general of DoA and Prof Robin Coningham, UNESCO chair in Durham, supported by Ram Bahadur Kunwar of the DoA and Christopher Davis, Jennifer Tremblay of DU and Anouk LaFortune Bernard.

Focusing on the durbar squares in Kathmandu, Bhaktapur and Patan, the team used Ground Penetrating Radar to locate subsurface archaeology to increase understanding of the development of heritage sites, and assessed the damage to foundations through excavations, offering invaluable training for Nepali professionals.

The surveys located archaeology under pavements and excavations confirmed the presence of earlier buildings.

“Our pilot investigations have illustrated the dynamic histories and developments of the three durbar squares as well as informed architects and engineers about the integrity of the foundations of the collapsed monuments, illustrating the resilience of traditional construction techniques through the centuries within a seismically active region, providing information that will aid the sympathetic reconstruction of collapsed and damaged monuments whilst protecting sub-surface archaeological heritage,” team leader Prof Coningham, DU, stated.

In Bhaktapur, researchers identified walls belonging to a monument which collapsed in the 1934 earthquake.

Additionally the team unveiled that modern pipes and sewers had damaged the rich archaeological deposits below.

In combination with the Ground Penetrating Radar survey, these results have allowed the creation of Risk Maps, which will protect subsurface heritage by guiding new water, power and sewer lines in the years to come.

“Whilst illustrating the complex pasts of the monumental Durbar Squares, the Archaeological Risk Maps will also guide reconstruction and future development of these historic sites to protect the subsurface heritage that these investigations have revealed,” Christian Manhart, UNESCO Representative to Nepal, explained.

“Capacity building in urban and rescue archaeology and investigations through the use of traditional excavations combined with geoarchaeology and Ground Penetrating Radar have not only enabled recording of the damage that the earthquakes caused, but also enabled the refining of guidelines for post-disaster recovery and reconstruction phase, highlighting the need for Kathmandu Office archaeological interventions to protect both standing architecture and sub-surface heritage, especially at Nepal’s monuments of Outstanding Universal Value,” said Bhesh Narayan Dahal, DoA director general.

According to UNESCO Nepal, the team identified that the collapse of many monuments may be linked to poor superstructure maintenance and noticed a common design of cross-walls, braced against large squared foundation walls, across the surveyed cities.

Excavating the foundations of damaged monuments, the team identified multiple phases, including an early timber and clay platform at Patan’s Char Naryan Temple and several phases of brick construction under Vatsala Temple in Bhaktapur.

Source: THT