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Risk Reduction and Preparedness in Nepal
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Bhaktapur's Durbar Square was one of the many monument zones of the Kathmandu Valley's UNESCO World Heritage Property to suffer damage in the 2015 Gorkha Earthquake. As part of a UNESCO-sponsored mission, national and international experts from the Department of Archaeology, Government of Nepal, Durham University and the University of Stirling were mobilized to undertake post-disaster archaeological surveys and rescue excavations by the Government of Nepal and Bhaktapur Municipality in November 2015. The archaeological assessments have provided new evidence for the origins and development of Bhaktapur and the Vatsala Temple as well as providing guidance for the future protection of Bhaktapur's significant but vulnerable subsurface heritage.
The two earthquakes that struck Nepal on the 25th April and the 12th May 2015 were a human catastrophe, devastating large areas of the county and neighbouring regions and leading to substantial loss of life and livelihoods as well as post-disaster physical and mental trauma. This natural disaster, and its associated aftershocks also generated a cultural catastrophe, damaging and destroying parts of Nepal's unique cultural heritage as well as traditional structures throughout the historic settlement devastated.
Due to the importance of this heritage to the daily cycles of Bhaktapur's community, and in recognition of the income generated through tourism, there was widespread agreement that a program of reconstruction and conservation should be
swiftly launched. However, while much of the damage that one can see is above the ground, it was also recognised that there was an unintended risk of irreversible damage to Bhaktapur's subsurface heritage from post-earthquake interventions and development.
Earthquake Damaged Monu- ments in Bhaktapur's Dur- bar Square
Today, Bhaktapur's main Durbar Square forms a large open space, although it was not always empty of structures as watercolours painted by Henry Ambrose Oldfield in the 1850s and photographs in the early twentieth century show the two-storied Lampati sattal, which collapsed in the 1934 Bihar Earthquake. Indeed, Nepal's Rana rulers used the impact of the earthquake as an opportunity to dramatically remodel the Durbar Square as an open arena by choosing not to rebuild the Lampati or the octagonal Chyasin Mandap, whilst stripping the ruins of the Hari Shankar Temple down to its lion sculptures.
The 1934 Earthquake also offered the opportunity to reconstruct other monuments in different designs, the most striking example of this being the Silu Mahadev or Fasi Dega (Tahacho Dega) Temple. Whilst the temple's five-stepped plinth survived intact, the deity's shrine was re- erected in a Neo-Classical style. Furthermore, the 55-Window Palace was reconstructed with the rapid reincorporation of wooden elements, diverging from traditional construction practices. Only during later twentieth century restorations were the latter
architectural elements rectified. Other buildings were reconstructed in accordance with their original forms, such as the Vatsala Temple, although with the use of lime surkhi to bind the stone blocks of its sikhara.
A number of the previously rebuilt or repaired monuments were again damaged during the 2015 Gorkha Earthquake. For example, the Neo-Classical Silu Mahadev shrine collapsed and several structures in the main Durbar Square sustained damage, including the palace complex and a brick Siva sikhara temple in the west of
the square. The most visible loss, however, was the collapse of Vatsala Temple, a monument dedicated to Vatsala Devi, a form of the goddess Durga. It is traditionally thought that the first monument dedicated to Vatsala was constructed by Jitamitramalla (r. 1673-1696 CE) in 1693, with a second completed by the same benefactor in 1696 CE. The present sandstone-built monument is believed to have been completed by Bhupatindramalla (r.1696-1722 CE) and most scholars agree to a construction date of between the late seventeenth and early eighteenth
century CE with a rededicated bell stand incorporated in 1721 CE. However, prior to this mission, no archaeological assessment had been conducted at the monument and postulated chronologies relied on inscriptions and architectural typologies.
As noted above, this was not the first time that the temple had been damaged as half its sikhara tower collapsed in the 1934 Earthquake. Although reconstructed afterwards, damage caused by the growth of a pipal tree led the Department of
Archaeology, with support from UNESCO and the technical guidance and assistance of Wolfgang Korn, to undertake a program of conservation between 1977 and 1978. This work included the dismantling of the northern portion of the tower as well as two corner pavilions and the replacement of a lintel above the arcade while the stone blocks of the tower reset in cement mortar. Indeed, many of the large fragments of the stone sikhara found in the Durbar Square after the earthquake were still joined by the thick mortar and bricks, some with visible mason marks engraved in Roman script.
While detailed architectural drawings and measurements of the standing architecture of the Vatsala Temple had been recorded during the conservation
program, nothing was known of its foundations although Korn did suggest generically that the foundations of stone built temples in the Kathmandu Valley were "made of boulders or lumps of coarsely worked stone".
2015: Archaeological investigations at Vatsala Temple and Bhaktapur Durbar Square
The post-earthquake archaeological assessments in the Kathmandu Valley included the undertaking of a Ground Penetrating Radar survey across the square as well as excavations adjacent to the foundations of the Vatsala Temple. It also included geoarchaeological sampling of the excavated sequences for dating and environmental analysis of Bhaktapur's ancient occupation.
GROUND PENETRATING RADAR SURVEY
Bhaktapur's Durbar Square presented the opportunity for us to undertake a broad subsurface survey in order to search for earlier phases of settlement and structures. Although used with success at Tilaurakot-Kapilavastu in the Terai (see SPACES 12.1), more traditional geophysical techniques such as magnetometer survey which identify variances in the magnetism of soils and structures below the ground cannot be used in these urban locations as the high magnetism of the brick paving on the squares' surfaces block out the signatures of archaeology below. Therefore a Ground Penetrating Radar (GPR) was used to survey below the paved square to identify architectural features, such as walls, from the reflection of radar signals.
The results in Bhaktapur's Durbar Square were spectacular, allowing us to identify many modern intrusive features such as pipes and electric cables as well as a number of anomalies that represented archaeological features. Several of the latter were rectilinear anomalies with their shape, size and layout suggesting walls. Indeed, the location of the GPR's rectilinear anomalies was very close to the footprint of the two-storey sattal depicted in Oldfield's 1850s watercolour.
Following the initial GPR results, it was excavated an 'L'-shaped trench that was 15 metres east-west from the western edge of the Vatsala Temple and then formed a right-angle and ran north for 12 metres. The team was
able to confirm the presence of the pipelines identified by the GPR survey but also recorded that these modern amenities had damaged and truncated earlier archaeological sequences. This illustrates the need for the completion of archaeological assessments prior to any intrusive digging across the Durbar Square or any site of historic and archaeological importance as unchecked below ground interventions can irreparably damage the finite subsurface heritage of these sites of Outstanding Universal Value.
The team also exposed an earlier phase of brick paving below the square's current paving. Laid in a herringbone pattern, it was believed that this surface represents the pavement laid shortly after the 1934 Earthquake as it sealed several
alignments of brick walls below, all truncated to the same height. Running north-south and east-west through the trench, these walls seem to be the surviving footings of walls levelled from the sattal that collapsed in the 1934 Earthquake and match the GPR results. One of the north-south walls showed evidence of a shear crack in its face and another was tilted and displaced. These indicators suggest evidence of damage caused by earlier earthquakes, most likely relating to the events of 1934 and it is postulated that the collapsed building was cleared after the earthquake and the pavement constructed across the tops of the walls levelled to roughly the same height.
Not only do these results reaffirm that Bhaktapur's Durbar Square was not
always so open and that structures used to stand where today there is only paving but they also illustrate that urban sites in the Kathmandu Valley have complex archaeological sequences below the ground that need protection from future development and potentially intrusive interventions.
When a trench adjacent to foundations of the collapsed Vatsala Temple western façade was opened, the temple's elevation bore the hallmarks of recent earthquake damage with the majority of the worked stone blocks out of place, shaken from their setting, with those that remained distorted and shifted from their original positions. Soon it became clear that the stone blocks only formed a veneer or cladding, which was not keyed together or keyed into the underlying brickwork. The removal of deposits adjacent to
the Vatsala's footings also showed that an earlier phase of construction lay below its current configuration. The later temple footprint both overlaid and overhung the earlier brickwork below. This suggests the presence of quite distinct phases of construction as well as earlier phases than previously thought.
Cutting through this phase of earlier brickwork was a wide and deep posthole. Due to its position, adjacent to the stairs on the western elevation of the Temple, it is postulated that it may have been a cut for a large wooden post. This was perhaps associated with a temporary structure, potentially a pavilion adjacent to the Temple or a more permanent nondurable appendage to the Vatsala Temple's frontage. However, due to its proximity to the location of the
collapsed bell on the Temple's stone frontage, it is also possible that the cut represents the location of a post for an earlier bell.
Whilst excavating, several indicators of past human activity were identified including thin charcoal and ceramic rich surfaces. Within these horizons of activity, we recorded several features which highlighted that human activity had occurred earlier in the open areas below the current paved surface of the Durbar Square and the need to protect and preserve these subsurface deposits from intrusive interventions.
The Vatsala's foundations were exposed once these features were recorded and excavated. During excavation, several soil horizons with the lowest deposits devoid of cultural material were encountered which
represent natural soil accumulation. The foundations of the Vatsala Temple cut through these earlier deposits, reaching a depth of 1.5 metres. The lowest three courses were constructed from stone cobbles, which varied in size and were placed irregularly.
This configuration partially confirms Korn's hypothesis for the foundations of sikhara style temples, with the lowest levels comprising cobbles and coarsely worked stone. Now
proved through scientific excavation, it is confirmed that the majority of foundations were constructed in brick. The lowest eleven courses of brick formed a fairly irregular foundation and were capped with regular brickwork. It is thus clear that there were several phases of construction in the vicinity of the Vatsala Temple and that any reconstruction of the final stone-clad phase of the temple needs to avoid damage to the earlier developmental sequence below.
Not only providing information for engineers and architects as to the design and nature of the structure's foundations, the excavations at Bhaktapur also offered a unique opportunity to develop new understandings of the early landscapes in which Bhaktapur's monumental architecture developed. As a result, the team completed geoarchaeological
examinations of buried soil profiles under the collapsed Vatsala Temple and the Durbar Square to analyse evidence of past cultural and natural environments. This analysis included examining the colour, texture, structure and frequency of deposits and Optically Stimulated Luminescence (OSL) samples were also extracted for scientific dating and soil samples for extracted for the analysis of microstratigraphy.
The resultant analyses have identified a distinct transition from sediments with common charcoal frequencies in the lower part of the stratigraphy to sediment dominated by brick inclusions in later phases. This is currently interpreted as a transition from rural to urban landscapes, with the limited charcoal content of the lower stratigraphy associated with background burning and agricultural management. However, the sites themselves were set apart from everyday domestic activity, with an
urban transition evidenced from the marked increase in frequency of brick fragments. Further analysis, linked to OSL dating, will provide a chronological framework that will allow us to relate this hypothesised transition to wider, regional, changes in climate, and understandings of whether periods of fluctuating environmental conditions may be the result of climate change or the process of urbanisation itself. It will also allow us to tie such changes into construction phases of monuments.
The OSL dating program will provide the first comprehensive approach to the dating of struc-tures in the Kathmandu Valley and, although still processing the
samples, preliminary results sug-gest that the foundations of the earliest brick structure underlying the later stone Vatsala Temple may be as early as the first century BCE. These are tentative dates and need additional analysis but they do suggest that the structural core of the Vatsala Temple site is far earlier than the current attributions of a seventeenth or eighteenth century date.
ARCHAEOLOGICAL RISK MAPPING
The recent investigations at the Vatsala Temple and within Bhaktapur's Durbar Square have pushed back evidence of human activity in the city by several centuries and have illustrated the extent of subsurface heritage at this
World Heritage Site. The GPR survey has also highlighted areas of potential archaeological features below the current square and excavations have revealed the character of some of these anomalies. As noted above, it is clear is that the Durbar Square was not always an open space but has a complex history of development. The current square is not in its original configuration but is the most recent footprint of an organic and opportunistic development, relating to earthquake damage and building programs in the past.
In addition to identifying historic human settlement within the square, investigations have also demonstrated that this heritage has been recently
damaged by modern interventions, including the laying of pipelines. Due to the high concentration of subsurface heritage at Bhaktapur, such modern interventions are a concern as the laying of any infrastructure has the potential to damage and destroy the subsurface heritage of this site of Outstanding Universal Value.
The damage caused by the 2015 Earthquake will require reconstruction and also the repair and laying of amenities across Bhaktapur. While the suspension of laying services is not recommended, there are reasons to advocate the mobilisation of archaeological teams to undertake rescue excavations in advance of such interventions. Archaeological Risk Map for Bhaktapur will provide information for site managers and stakeholders as to the risk posed to subsurface heritage and help guide future development.
These Archaeological Risk Maps highlight those areas where
archaeological vestiges, both on the surface and below the surface, are at risk from development. Using a traffic light system of Red, Yellow and Green, these designated areas come with recommendations for site managers and planners on how to guide the subsequent physical planning and development within a site. It is recommended that Risk Maps based on the results of the initial GPR survey and excavations should be used to guide and aid future subsurface interventions within Bhaktapur's Durbar Square, including the repair of below ground infrastructure damaged by the earthquake.
From the observations and investigations, we feel there needs to be a heightened awareness that the cultural heritage of Bhaktapur is not restricted to its standing remains but needs to take account of the deep foundations of these monuments and also the dense concentration of earlier phases of cultural activity found below the current brick paving of the main
Durbar Square. The Archaeological Risk Maps and our interventions should facilitate the dissemination of this awareness and highlight that subsurface heritage needs to be protected.
The post-disaster archaeological investigations have demonstrated the complex development of Bhaktapur's Durbar Square and provide a valuable case-study of the dynamic nature of the Kathmandu Valley's urban centres. Rather than representing monumental cores laid out in single static configurations from their initial establishment, our research shows that monuments were erected and removed over time, in some instances related to opportunism brought by natural disasters, such as the 1934 Earthquake. The levelling of damaged structures below public squares is not unique to the Kathmandu Valley as it is also recorded across medieval Europe, such as in the Piazza Duomo in twelfth century Italy.
This process was more recent in Bhaktapur and many of Bhaktapur's lost monuments are within the consciousness of historians, architects and archaeologists. However, such knowledge has not averted intrusive interventions that have damaged the subsurface heritage of Bhaktapur. The GPR survey has illustrated that there is a high density of earlier structures and archaeological remains across the Durbar Square and our investigations has found evidence of damage from modern pipelines. This reaffirms the need for archaeological assessments prior to construction work within the site with the Archaeological Risk Map guiding any development or reconstruction that may occur.
The UNESCO sponsored excavations have also provided the architects and engineers tasked with reconstruction scientific evidence for the phasing, dating and construction techniques of the Vatsala Temple and monuments exposed across the square. This also includes some observations on what may have contributed to the collapse of the Vatsala
human activity below that had not been previously known; at least three phases of brick construction, with a later stone phase, again illustrating the constant development and adaptation of monuments. The geoarchaeological evidence suggests that the monument may have been constructed as early as the first century BCE and also highlights the early urbanisation of the Kathmandu Valley, with the background environment changing from rural to urban. While such dates still need refining and may change through further detailed analysis, the archaeological investigations reaffirm that we do not yet know the full story of the monuments of the Kathmandu Valley or the history of Bhaktapur. The dates provided in epigraphs and chronicles provide only a partial picture of the history and development of the historic sites of its cities and further archaeological investigations and geophysical surveys are required, especially with a focus on subsurface heritage to fully understand the origins and histories of these sites of Outstanding Universal Value.
In addition to working at Bhaktapur during our November 2015 UNESCO Mission, investigations were also conducted across Patan's Durbar Square and at the Char Narayan Temple as well as in Hanuman Dhoka's Durbar Square and at the Kasthamandap. Continuing investigations at the Kasthamandap in 2016 and at several sites across the Kathmandu Valley with support from the UK's Arts and Humanities Research Council, the National Geographic Society and the Department of Archaeology, Government of Nepal, our collective research is demonstrating the value of interdisciplinary archaeological investigations in post-disaster environments. As well as providing assessments of the condition of foundations of collapsed monuments, it began to piece together the forgotten pasts of these monuments, not only aiding their reconstruction in the present but also reconstructing their pasts through research-driven rescue archaeology.
Temple; in this instance, the lack of bonding between the stone masonry and the weight of the stone sikhara. The lack of bonding and the weight of stone blocks for the cladding left the Vatsala open to the displacement of its masonry during the earthquake. Indeed, unlike many monuments that were damaged in 1934 and not in 2015, or vice versa, the Vatsala Temple has now been badly damaged in both seismic events, suggesting a structural flaw in the interface between the monument's superstructure and foundations – but one which can't be fully understood until complete excavation is undertaken.
The excavations have also provided a sequence for the Vatsala Temple site, uncovering earlier phases of
We would like to acknowledge the support of the following individuals and institutions for their help and expertise in the field and during the archaeological activities: Narayan Man Bijukchhe MP, Mr Prem Suwal MP, Mr Bhesh Dahal, Mr Bharat Subedi, Mr Christian Manhart, Dr Roland Lin, Mr Kai Weise, Mrs Nabha Basnyat-Thapa, Mrs Nipuna Shresta, Mr Chaitya Raj Shakya, Mr Uddhab Rijal, Mr Damodar Gautam, Mrs Saubhagya Pradhananga, Mrs Aruna Nakarmi, Mrs Mangala Pradhan, Mrs Pratima Ranjit, Mrs Manju Singh Bhandary, Mr Bishnu Prasad Pathak, Mr Ram Govinda Shrestha, Mr Om Kumar Shrestha, Mr Raj Kumar Banjara, Mr Jagat Bahadur Katuwal, Miss Anita Timilsina, Miss Shanti Sherma, Miss Sunita Bhadel, Mrs Maiya Kaiti, Mr Bikash Nakarmi, Mr Ranjan Dulal, Mrs Sita Phuyal, Dr Jennifer Tremblay-Fitton, Ms Anouk Lafortune-Bernard, Ms Emilia Smagur, Dr Paolo Forlin, Dr Mark Manuel and the staff and students of Khowpa Engineering College, Bhaktapur.
We would like to thank UNESCO for their financial support and the assistance provided by the UNESCO Kathmandu Field Office, as well as institutional support from Durham University and the University of Stirling. Finally, we would like to thank the Municipality and communities of Bhaktapur for their support and interest in our mission.
For more information please visit https://www.dur.ac.uk/cech/unescochair/research/kathmandu