Tokyo National Research Institute for Cultural Properties Center for Conservation Science
Department of Art Research, Archives and Information Systems Japan Center for International Cooperation in Conservation
Department of Intangible Cultural Heritage

Archaeological Investigation and Risk Assessment for the Conservation and Management of Ta Nei Temple in Angkor, Cambodia (Part II)

Excavated terrace structure
Survey of the current condition of the temporary supports

 The Tokyo National Research Institute for Cultural Properties has been carrying out technical cooperation with the Authority for the Protection and Management of Angkor and the Region of Siem Reap (APSARA) in order to draft a conservation and management plan for Ta Nei Temple in Cambodia. From November 28th through December 8th, 2017, we conducted an archaeological investigation and a risk assessment for the structures at Ta Nei Temple for the second time.
 The main purpose of the archaeological investigation was identifying the remains of the east approach to the temple located at its front and the remains of a structure situated on the upper surface of the embankment of the East Baray reservoir discovered during the first investigation in July. The excavation was conducted jointly with staff from APSARA and with the cooperation of the Nara National Research Institute for Cultural Properties.
 First, we set up and excavated a trench 2 m wide from east to west and 5 m long from north to south, approximately 50 m to the east of the east gate. We discovered a hardened surface, presumably the old approach to the temple, 70 cm beneath the current ground surface. The hardened surface was composed of yellow soil covering a layer of small sandstone gravel 5 mm in size overlapped on a layer of fist-sized sandstone cobbles.
 In addition, we set up and excavated a trench 11 m long from east to west and 1 m wide from north to south on the embankment of the East Baray on the prolongation of this approach way. We found a laterite stone surface 30 cm beneath the current ground surface (Figure 1). Considering the surrounding topography and the distribution of exposed laterite, these remains can be presumed to form part of a terrace structure approximately 20 m long from east to west and 15 m wide from north to south.
 Regarding the risk mapping of the site, we examined how to renew the existing temporary supports. Wooden supports had been installed in 16 places where there were safety concerns such as potential collapse of main structures, including the central tower, the east tower, and the inner gallery. However, apart from obstructing the view of the site, these supports are in need of renovation, as in the 20 years that have passed since their installation decay of timber members and loosening of joints have become apparent. Thus, we observed and recorded the current condition of these supports, and studied improvement proposals including a change to a more durable material and the adoption of a design enabling fine adjustment.

Participation and Presentation at the 19th ICOMOS General Assembly and Scientific Symposium

The General Assembly

 The 19th ICOMOS General Assembly and Scientific Symposium was held in Delhi, India from 11th to 15th December. The author took part in the General Assembly and made a presentation at the Symposium.
 During the General Assembly, the triennial elections for the Executive Committee were held. Professor Toshiyuki Kono from Kyushu University was elected as president, becoming the second Asian and first Japanese president of ICOMOS since its foundation in 1965. Professor Kono has had a leading role in several initiatives engaging current issues surrounding cultural heritage from multiple perspectives, including the Convention for the Safeguarding of the Intangible Cultural Heritage, the Nara+20 Conference and the ICOMOS Project on Cultural Heritage Recovery and Reconstruction. The further development of such initiatives during his three year term is highly anticipated.
 In addition, the General Assembly officially adopted the “Principles for the Conservation of Wooden Built Heritage”, redacted by the ICOMOS International Wood Committee (IIWC). This document is an updated version of the 1999 charter by the same committee. The updated version is more detailed and concrete, while at the same time placing a renewed emphasis on the intangible aspects of wooden built heritage.
 The General Assembly also saw the adoption as one of its resolutions of a proposal redacted by the Emerging Professionals Working Group, aimed at strengthening the involvement of emerging professionals in the activities of ICOMOS.
 At the Scientific Symposium, under the title “Heritage and Democracy”, speakers from different countries presented initiatives aimed at involving actively in the conservation process the local communities and other stakeholders who maintain, use and safeguard the heritage. As an example of such initiatives in Japan, the author made a presentation on the “heritage manager” system.

Archaeological Investigation and Risk Assessment for the Conservation and Management of Ta Nei Temple in Angkor, Cambodia

Risk assessment
Trench excavation and the ditch revealed (created with SfM)

 The Tokyo National Research Institute for Cultural Properties is providing technical support to the Authority for the Protection and Management of Angkor and the Region of Siem Reap (hereafter APSARA) to draft a plan for the conservation and management of Ta Nei Temple. From July 16 to 30, 2017, we carried out an archaeological excavation and risk assessment of the buildings (Figure 1).
 Our excavation was mainly to identify remains of the East Approach to the temple, located at its front. We worked with APSARA staff with the cooperation of the Nara National Research Institute for Cultural Properties. When we cleared the underbrush along about 100 meters from the Eastern Gate of the outer enclosure to the East Baray reservoir, we discovered remains of a laterite terrace on the bank of the reservoir, suggesting the high likelihood of this location being the starting point for an approach leading to the Eastern Gate.
 We first opened a trench measuring 2 meters east-west and 10 meters north-south about 12 meters east of the Eastern Gate (Figure 2). Our excavations revealed a ditch running east-west 50 cm below the current ground level. The ditch was about 2 meters wide and filled with amounts of fine chips of laterite (1cm-0.5cm in diameter), suggesting the possibility of an approach. In addition, both sides of the ditch were covered with fist-sized sandstone cobbles.
 For the purpose of finding the rest of this ditch as well as to verify the initial ground level, we opened a trench measuring 2 meters east-west and 2.5 meters north-south along the Eastern Gate and dug down. This trench revealed a sandstone cobbles covered surface that spread out over the entire surface 50 cm under the current ground level, and we were unable to detect any remains of the ditch.
 We are planning another excavation in November to determine further details of the Eastern Approach and to identify the entirety of the newly discovered terrace-like remains.
 One of the major charms of Ta Nei Temple is its ancient ruin-like setting, relatively untouched by human hand compared to other Angkor ruins. On the other hand, there is a need to prevent further collapse, in part to ensure the safety of visitors. Therefore, it is urgent for support structures to be installed and updated in a planned, organized manner on the basis of structural risk assessment of the overall temple complex. We decided to create elevation maps using SfM and conduct a risk assessment starting from the major buildings along the central axis. We started with two buildings with which we worked to establish the procedures for such operations. This work is currently being continued by APSARA staff.
 To preserve the buildings and surroundings in good condition, as well as to help visitors to the area better understand the significance and value of the site, we wish to intensify our cooperation toward academic elucidation and achievement of effective conservation.

Holding the seminar “Ancient Wooden Architecture in Mainland Southeast Asia: Reading the Features of Lost Buildings from Archaeological Evidence”

One of the lectures of the seminar

 The seminar “Ancient Wooden Architecture In Mainland Southeast Asia: Reading The Features Of Lost Buildings From Archaeological Evidence” was held on 13 February 2017. In this seminar, experts from
Myanmar, Thailand, Cambodia, Vietnam and Japan made presentations on the developments on this field in each country, shared information and exchanged opinions.
 In their presentations, the lecturers explained the different efforts being carried out in each country in order to determine the features of already lost wooden buildings from the remaining archaeological evidence. In Myanmar, large postholes shaped as wells and surrounded by bricks have been unearthed at the Bagan Royal Palace site. In Thailand, foundation stones, unearthed roof tiles, and traces of wooden members remaining in masonry walls and pillars have been used as hints to deduce the features of the wooden posts, walls and roof structures that existed in the sites of Sukhothai and the Phitsanulok Royal Palace. In central Vietnam, foundation stones, ornamental eave-end tiles and burned wooden members have been excavated from several Lin Yi sites, and reconstruction proposals of wooden structures have been developed on the basis of postholes found at the Champa site of My Son. Regarding northern Vietnam, the features of the foundation works and unearthed roof tiles at the Thang Long Imperial Citadel site were introduced, and a comparative analysis between earthenware architectural models and existing ancient buildings was made.
 A question and answers session was held after each presentation, and at the end of the seminar a panel discussion with the participation of all the presenters was held, including the Japanese approach among the discussion topics.
 The results of the fruitful exchange of information carried out during this seminar will serve as a basis for future cooperative research efforts, directed at furthering the understanding of the wooden built heritage of Southeast Asia.

Survey on Quake Damage in the Ruins of Bagan, Myanmar

 On August 24th, 2016, a magnitude 6.8 earthquake with its epicenter in the central part of Myanmar struck; as a consequence, the ruins of Bagan, one of the representative cultural assets of the nation, suffered serious damage. The group of ruins in the region includes more than 3,000 brick Buddhist stupas and small temples built mainly in the 11th to 13th centuries. According to the Department of Archaeology, National Museum and Library, Myanmar Ministry of Religious Affairs and Culture, 389 of these sites were discovered to have been damaged (as of the end of October 2016).
 Following the dispatch of an advance inspection team in September,2016, the Tokyo National Research Institute for Cultural Properties (TNRICP) was commissioned by the Agency for Cultural Affairs to oversee a project to provide emergency aid and sent a party of eight specialists (on conserving cultural assets, repairing buildings, structure of buildings, and surveying) to the sites with the aim of identifying the actual state of quake damage to valuable cultural properties, from October 26th through November 10th, 2016. They conducted surveys from four standpoints, namely, the situation of damaged historical buildings, the structural analysis of damaged buildings, the situation of emergency protective measures, and the analysis of records of damage.
 The ruins of Bagan sustained quake damage in 1975 as well, and a large number of structures had been restored or rebuilt thereafter. As a result of the current inspections, however, it was discovered that much of the damage from this earthquake was concentrated on the newly reconstructed parts or the boundaries between the newly repaired parts and old parts, such as a tower of the upper part of a building. Moreover, deformation or cracks existing in vaults, walls or podiums owing to age are believed to have been aggravated by the earthquake. Meanwhile, thanks in part to prompt actions by local residents and volunteers under the leadership of local authorities, emergency protective measures appear to have been taken in an expeditious manner.
 With an eye toward subsequent restoration, we must identify the cause and mechanisms of damage by not only conducting further inspection but also discussing the technical and philosophical issues that are common to the conservation of brick architectural heritages in earthquake-prone regions, such as how to reinforce a structure, melding of traditional techniques and modern counterparts, and the validity of reconstructing damaged parts.

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