Rebuilding Nepal for Next Earthquake

Jul 10, 2017 |

TEXT : Er. Badan L. Nyachhyon

The April 25, 2015 Nepal Earthquake created huge damages to life and properties in Kathmandu Valley and 28 other Earthquake affected districts along with massive landslides and avalanches in Mount Everest and Lamtang Himalayas. Strong aftershocks counted over 425 had drastically weakened the remaining building stock, which has created unaccounted strain on the recovery plan. By that time, many of the buildings either will be dismantled without any rationale and post mortem study or rebuilt at the owners’ risk without any value addition of retrofit, recovery, protection of assets and ancient values. Surely, the need for deriving lessons and confidently facing challenges of recovery is paramount for enhancing the safety from future earthquakes.

The Earthquake did not forgive the negligence shown in effectiveness of implementation of Building Codes, assurance of quality construction and proper utilization but it has become the source of huge casualties. Particularly, the massive destruction of 745 cultural heritage monuments comprising of traditional vernacular esthetics in the form of temples of centuries old, 850,000 building units collapsed or damaged spread in numerous traditional urban settlements and destruction of the ability to demonstrate wisdom are the big challenges for post earthquake recovery. These world heritage assets and the physical outlook of the settlements will never be the same again and will repeat the same fate with ad hoc reconstruction in the absence of guided recovery plan.

Many people expect that the professional Diaspora should come up with identified means to predict the potential future earthquakes. The process of identification of methods to predict a potential earthquake may be still a distant fact but the need for observation of local ground movement around the places of concerns are brightly visible. The tension cracks along the hill slopes are potential threat of massive avalanche to inundate a hydropower or wash it out or a local micro crack of Harihar Bhawan-Machagal-Kumaripati ground crack, Sunkosh Landslide of 2014 and Mustang dry landslide of 2016 could be pre-warning of potential immediate earthquake. The vigilance is most wanted. But the question is who takes the leadership and ownership the earthquake affair.

However, the cities of Kathmandu Valley do not give impression that they were stricken with a deadly Earthquake with Peak Ground Acceleration of 1.2g much exceeding previous records of 0.52g. The whole world expected a flattened Nepal. But to the contrary, amid the vast destruction of poor quality and weak construction, the whole city including most of the cultural heritage sites, high rise buildings and residences are marvelously standing safe and intact. The credit for this state-of-the-art performance goes to the stakeholders who had worked hard during last 30 years to create Earthquake resilient community following the provisions of Building codes and requirements of quality construction. But, however, the challenge remains aggravated with the lack of coherent vision, acceptable Earthquake model, ownership of the Earthquake affairs in general and rebuilding policy for Next earthquake.

The overall scenario of the cities in Nepal after the April earthquake did not resemble the scenario of earthquake stricken cities but of a normal one with visibly intact cityscape. The most of the vital infrastructure as water supply and sanitation facilities, electricity, telephone, internet, roads and bridges, and airports remained unaffected and the services were not interrupted. That was very instrumental in effective delivery of the international and domestic relief works across the affected 14 districts. The damages though accounted as significant did not extended to the magnitude forecasted by previous studies. The estimated and
actual casualties and damages are presented in Table 1.

Apart from the damages of the buildings that had made over 4.5 million people homeless, numerous landslides and rock falls were triggered in the mountain areas, temporarily blocking roads.

It was known to all that a large earthquake is inevitable and the only way to face such earthquakes is to make adequate preparations. Various tasks that were very glaringly visible such as need for updating building codes and urban development bylaws, removing the weaknesses and mischief in them. Despite for several voices called for paying attention on need for declaring policy on building Earthquake Safer cities and protecting important premises as historic cultural monuments, schools, hospitals, industries, communication and tourism infrastructure, the country has no pronounced program to the effect needed. The priority of actions for conservation of heritage and cultural values verses modern engineering technology needs to be established. The encouragement and motivation factors for investment in Earthquake Safer Cities are still missing. This state of adamant situation cannot be anymore continued.

The USGS quick report on the April 25, 2015 Gorkha Earthquake made reference to very large Nepal earthquakes, with a moment magnitude of 7.5 or more, observed in the historic periods in 1100, 1255, 1505, 1555, 1724, 1803, 1833, 1897, 1947, 1950, 1964, 1988. Three earthquakes of similar size to the Gorkha Earthquake occurred in the Kathmandu Valley in the 19th Century: in 1810, 1833, and 1866. The seismic record of the region, extending back to 1100, suggests that earthquakes of this size occurred approximately every 75 years, indicating that a devastating earthquake is inevitable in the long term.

The strong motion network of Nepal is quite limited. Nevertheless, Kanti Path (Kathmandu) recorded the maximum ground acceleration of 0.164 g. The USGS preliminary estimation of the maximum ground acceleration (PG A) in the epicenter area was about 0.35g and 0.1 - 0.15 g for Kathmandu. In Western Nepal, PG A range was between 0.5 g and 0.6 g, whereas in Eastern Nepal that ranged between 0.3 g and 0.6 g. The PG A estimate was based on the empirical relations developed by Aydan (Aydan and Ohta, 2011; Aydan 2007, 2012).

Mr. Jean Ampuero, California Institute of Technology, in his paper “Salient Features of the 2015 Gorkha, Nepal Earthquake in Relation to Earthquake Cycle and Dynamic Rupture Models” indicates that the high-frequency (HF) ground motions produced in Kathmandu by the Gorkha Earthquake were weaker than expected for such a magnitude. The static slip reached close to Kathmandu but had a long rise time. An important observation (Katsuichiro Goda, Department of Civil Engineering, University of Bristol, Bristol, UK and et el) is that the ground motion shaking in Kathmandu during the 2015 main shock was less than the PG A estimates (with 10% probability of exceedance in 50 years i.e., a return period of 475 years). This may indicate that ground motion intensity experienced in Kathmandu was not so intense, in comparison with those predicted from probabilistic seismic hazard studies for Nepal. Therefore, a caution is necessary related to future earthquakes in Nepal because the 2015 earthquake is not necessarily the worst-case scenario and more intense Earthquakes may be in making.

The surface deformation measurements including Interferometric Synthetic Aperture Radar (InSAR) data acquired by the ALOS -2 mission of the Japanese Aerospace Exploration Agency (JAXA) and Global Positioning System (GPS ) data were inverted for the fault geometry and seismic slip distribution of the 2015 Mw 7.8 Gorkha Earthquake in Nepal. The rupture of the 2015 Gorkha earthquake was dominated by thrust motion that was primarily concentrated in a 150-km long zone 50 to 100 km northward from the surface trace of the Main Frontal Thrust (MFT), with maximum slip of ~ 5.8 m at a depth of ~8 km, and 1.5 m at surface in Kathmandu Valley. In 1988, Roger Bilham estimated this slip would be of magnitude of at least 10 m (Figure 1). Thus, based on the observed values of Maximum Land Slip and the Maximum PG A, the April Earthquake could be termed as a Grand Rehearsal for the potential future earthquakes in Nepal.

Most of the existing buildings stock in rural and urban areas comprises of Non-engineered traditional construction of Brick/stone in mud mortar, and recent buildings in cement and RCC structure. In the aftermath of the April Earthquake, it is assumed that over 80% of the damaged buildings fall in the first category of brick and mud construction, and remaining buildings to second category. Though there is no post earthquake detailed vulnerability assessment report of damaged and existing building stock available at this time. However, it is absolutely necessary to determine whether the existing building stock can withstand the next Most Considered Earthquake or Design Earthquake. This question demands for carrying out a detailed vulnerability assessment of the building stock covering four issues: 1) lack of documentation of the building stock, 2) Updating of building code with consideration of recommended Design Earthquake Model. Many of these buildings are not designed to sustain that kind of load; 3) construction quality and change in occupancy, and 4) maintenance (Samir Chidiac, McMaster University, May 21, 2008).

One of the most immediate action carried out in Nepal immediately after the earthquake was the rapid visual vulnerability assessment of buildings. But the action faced controversy because of lack of adequate preparation and legal provisions. The tools used were informally borrowed from ATC 40 without proper legal backup and training. Most controversial action was the issue of Stickers (Green, Yellow and Red) categorizing the buildings into Safe, Caution, Unsafe (Figure 2). The actions created confusion in the community about its rationale and appropriateness. Surely, that was the result of lack of preparedness for such rapid action. The stickers were the good example of lack of adequate preparation. They were issued in very unprofessional manner and illegally since there were no such laws or guidelines that provide authority to do so. The Rapid Vulnerability Assessment forms were borrowed from elsewhere without authorization, proper guidelines and did not match with the typology of the buildings in the country.

The distribution of the category of these buildings is not known. There are two major challenges: 1) Demolition of collapsed buildings and disposal or reuse of debris, and 2) Rehabilitation of Partially damaged buildings and buildings with minor damages. The general psyche is that buildings with cracks (whatever may be the extent and cause) are no more useful for habitation and many started demolition without giving any thoughts on potential for restoration or rehabilitation. That has created strain on building stock deficiency creating huge price rise on rental. But the rational for recovery is on rise.

Quick recovery of damaged buildings immediately after the Earthquake was a very important aspect that would reduce the strain on the building stock. But in the absence of recovery guidelines, access to resources as technology of recovery and financing, the people gradually lost the nostalgia of the earthquake and started recovery on their one way, mostly guided by the approach to quick repair and to demonstrate that the buildings were not affected by the Earthquake. They
could no more wait for proper things to happen but to make efforts to quickly make financial recovery through use of the premises at the earliest, neglecting the safety issues. The buildings demolished during the relief works period was never recorded and analyzed to discover the root cause of the damages and actual effect of the Earthquake.

Most challenge is faced by the traditional residential buildings and heritage monuments with vernacular aesthetics that represented the identity of the country and carried the value of history and culture of over 2,500 years. Recovery of these buildings in the original form and shape would be a strain on investment unless specific measures are taken to recover the lost heritage and generate economic return. There are several approaches being forwarded under the principles of “Integrated settlement development” which will be developed following massive dismantling of damaged buildings to give an outlook (Figure 3) of the traditional aesthetics. This will be totally new construction and nothing will resemble of the value of history and culture carried by these settlements. Contrary to these, the modern trends for quick recovery will change the landscape dominated by modern technology that will lead to the extinction of the ancient values. This will be a total loss of the whole heritage assets. The broad objectives of these reconstruction as stated are 1) To provide safe living and healthy environment by repairing and reconstructing houses of the local residents, 2) To protect the traditional architecture, 3) To develop infrastructures, 4) To promote local business, 5) To increase income of local residents by promoting the tourism- oriented business, and 6) To conduct programs in social buildings and open space for encouraging social interactions.

Though the reconstruction program has the protection of the traditional architecture in its objectives but has not included the conservation of heritage and historic values of 2500 years. Possibly, we are wondering in the huge score of nomenclature associated with the post earthquake recovery i.e. Building Back Better, Rebuild, recovery, retrofit, renovation, rehabilitation, protection, conservation and reconstruction. Until we clarify what we want, it is sure that we will be swept away by the flood of the funds being poured in the reconstruction. The money power of immediate resource mobilization is much stronger than professional strength that is struggling with lack of resources and time. Some of the live cases where the regeneration based on the recovery of cultural heritage settlements promoted under the principle of “Conserve and Earn” have carried the message for paying attention on heritage conservation. These schemes are getting more popular as “Home stay” tourist accommodation. Some of the examples are: Shrestha House and Swotha Café (Figure 4). The innovative concept of “Conserve and Earn” was recognized by UNESCO and given “World Heritage” recognition. These structures did not suffered during Gorkha Earthquake.

Nepal Building Code Deficiency
Nepal Building Code is divided into four sections: Part 1) State-of-the-Art Buildings, Part 2) Professionally Engineered Buildings, 3) Non-Engineered Buildings (Mandatory Rule of Thumb), and 4) Rural Construction. The code is divided into 22 parts and the seismic design method is specified in NBC 105. In the preface, NBC 105 has included IS 4326 - 1993 Code of Practice for Earthquake Resistant Design and Construction of Buildings as related code. There is a marked difference between these two codes with various values of the seismic parameters and giving different results. This anomaly has confused most of the practicing engineers and NBC is practically not used. Other factor affecting the use of NBC is the nonaccessibility of International software as SAP, ETAB and STAAD Pro where NBC is not included as one of the recognized Codes.

Some of the cultural heritage monuments restored with International assistance suffered severe damages and totally collapsed (See Figure 5). Probably, Earthquake resistant construction of these monuments was not in their task.

Similarly, there are few instances where the structures of cultural heritage were intervened and damaged them by local authorities post Gorkha Earthquake (Figure 6). The temporary timber struts were erected without any purpose and without any knowledge of the technical unit of the municipality and without consultation with local community. After some time the struts were removed again without any information and taking any measurement of strengthening or precaution.

These factors are considered the lack of ownership at the Government level and lack of consultation with the professional and local community. More complex is the situation in Nepal where the need for following other international codes is paramount since Nepal Building Code in itself is inadequate and incomplete (Box 1). There is a dare need for updating the Nepal Building Code making it independent from other codes or reduce it to a guideline that will help to make choice of better codes.

In the Gorkha Earthquake Damage Survey report recommended that a basis for seismic design may be considered the PGA estimates with 10% Probability of Exceedance in 50 years as the design earthquake model for Nepal. Given consideration of earthquake design parameters, the level of risks of structures will depend on the choice of Building code selected. Hence, the level of risk in every project becomes different and level of earthquake hazard risk in Nepal also becomes heterogeneous based on the source of funding sources. Having said all above issues, it is imperative that the consistency of design principles is lost and the compliance to the Building Code requirements or application of correct design criteria and analysis is assured.

After the donors meet called by the Government in May 2015, the International Community and the country as a whole expected that rebuild initiatives will be launched very quickly and the recovery initiatives will be started. The Government’s effort to establish an independent authority met the political and legal jargon and was practically went to coma. The Government’s post earthquake instructions, related to 1) building bylaws restricted new construction until further notice, 2) reduction of interest for bank loans, 3) short training of fresh engineers and 4) finally the nomination of National Rebuilding Authority, became redundant because of inadequate home work and preparation and could not be formally established even after 6 months. The lack of consultation with experts and unilateral decisions were quite visible. The Government’s attitude of “Making the Decision in Haste and Repent in Leisure” was very prominent.

The well-wishers from all over the world are quite in panic that Nepal could not practically gear up for post earthquake recovery and loosing time. There were practically no guidelines for post earthquake recovery and rebuilding. People started repair and recovery without any engineering or government support and many of the buildings started to return to the same status as before. There is a strong voice that Nepal should learn from the experience of Earthquake Recovery from other countries as Japan and New Zealand and should send Fact Finding missions for learning the lessons and developing right approach and
policy. The New Zealand’s approach of post earthquake recovery through nomination of the Rebuild Team comprising of industry representatives ie the government, consultants, contractors, bankers, suppliers and manufacturers, insurance and community was a unique model that helped New Zealand to recover from 2011 Earthquake in a fast track manner with most effective way in terms of cost, time saving and employment creation.

Recently, the September16, 2015 Earthquake with magnitude 8.3 Mw in Chile caused only 13 fatalities. Why only 13 fatalities in this earthquake, which is considered the world’s strongest earthquake to date this year. While far weaker earthquakes in Haiti and, more recently, in Nepal, killed tens of thousands? The Chileans very proudly report that the resilience of Chile has three dimensions: a) Strong evacuation plans in coordination with international community as the UN humanitarian affairs office and the International Search and Rescue Advisory Group [Insarag], b) Strict building code that demand all new buildings must be able to survive a 9.0-magnitude earthquake. The buildings can crack, tilt and even be declared unfit for future use but it must not collapse and c) Strong sensitiveness to the Earthquake Disaster carried by Ricardo Toro , a former army general, in-charge of Chile’s disaster relief agency, ONEMI. The lack of institutional model for rebuilding and generally dealing with Earthquake Affairs in general is instrumental in the context of current chaos in Rebuilding Arrangement.

There are very few buildings and structures in Nepal which were insured against earthquake damages. But the insurance as such has hardly helped to recover the losses due to earthquake damages. The insurance policies of most of the Insurance companies of Nepal has hardly defined the effect of Earthquake and paying mechanism for the losses. Insurance companies define the earthquake damages within four corners of the buildings (even don’t care about the four corners of foundation) and don’t consider about the effect on foundation as foundation soil consolidation and risk associated with it, minor tilts and settlements in foundation, and need for taking protection needs. The gaps in Insurance payable damages shall be carefully included in the Rebuild Policy.

Given the situation in Nepal where there is a big gap in terms of ownership of earthquake matters, a lot of unscrupulous actions emerged that has created panic within the community and created negative image. The issue of Red and Green Stickers described above is an example. The post earthquake scenario and delay in organizational set up for post earthquake recovery actions has made it paramount for establishing an independent and autonomous apex bode - Earthquake Safety Commission. The leadership created through the Commission will be beneficial for permanent surveillance, developing policies and strategy, performance monitoring and evaluation, timely review and updating, and building consensus, which will be instrumental in creating Earthquake Resilient Society.

Protecting existing building stock of Nepal counting over 5.5 million is a big challenge in itself. There is not a single building, particularly the mud-brick/stone-timber buildings that are not affected by the Gorkha Earthquake. The biggest threat is from the society that view demolition is the best way in three ways: 1) The building does not to them or owner is from the different community or a neighbor, 2) It is the easy way to be safe from the risk it is associated with irrespective of the actual physical condition, and 3) There is no funds or technical assistance available for detailed damage assessment and determining the wisdom of demolition or protection through utilizing retrofit techniques. Surely, when wisdom fails, the flatterers prevail. Demolition and reconstruction of 5.5 million houses is not a factor any economy can afford, and not for Nepal as well. If we look at demolition of these 5.5 million houses to be replaced, probably Nepal will never rise again. Nepal needs a stitch in time and this is the time. Protecting the existing Heritage monuments, residences, schools, hospitals all needs to be fairly assessed. There are several tradition houses waiting for damage assessment and technical assistance for strengthening. Nepal Reconstruction Authority needs to look seriously to extend a package of technical assistance, which will be the most wanted step towards protection of national assets.

The other day of the April 25 Earthquake, Sriyesh Nyachhyon, age 7 years, Grade 2 GEMS School, made his expression about his first experience of the Earthquake. He said, “Yes. I know why earthquakes come. They come to test how strong our houses are. The strong ones stand firm and the weak ones fell down.”

Nepal is a highly earthquake prone area with noted earthquakes of magnitudes 4-5Mw two times a year, one in summer and one in winter. The Gorkha Earthquake of April 25, 2015 is considered as a grand rehearsal for future potential earthquakes. The large energy accumulated in the Himalayan Range, particularly around Kathmandu, that could rock the area with a land slip of 10 m is not fully released since the land slip was just 1.5 m.

The huge toll of life over 8,900 and loss of property about 600,000 collapsed buildings and 500,000 damaged buildings, though a very sad result, is considered significantly much less damage compared to the loss estimates of previous studies. This is a positive achievement of the efforts made during decade towards creating Earthquake Safer Cities. At the same time, it is also considered that pre-earthquake preparation was grossly inadequate. Nepal’s Earthquake resilience march carries a huge score of challenges. In the wake of recent earthquake and next potential disastrous earthquake, Nepal needs to rebuild over 800,000 buildings and strengthen other existing 5.5 million buildings of adobe construction. Apparently, there is no effective technology to restore, rebuild and strengthen the existing adobe construction. At the same time, updating of the building code and its strict implementation that would help to assure Earthquake Resilient Society is of essence in terms of assessment, planning, implementation in a timely manner.

The rebuilding initiatives already have been delayed and disappointed the whole world and the devastated people. But the Government is still not in move. This is a very pathetic situation, aggravated by the economic embargo of September 2015 that will further delay the progress of rebuilding and overall progress. The country is slowly going back to the same status of vulnerability it was before the earthquake.

From the various messages, it could be concluded that the Nepalese Diaspora have a very good knowledge about the essence of Earthquake resistant construction needs. But the deficiency is the national policy that still has to take appropriate shape and deliver the services.

Department of Urban Development and Building Construction, Government of Nepal Society of Consulting Architectural and Engineering Firms Structural engineers Association of Nepal Society of Nepalese Architects Nepal Engineers’ Association Indian Chapter of American Concrete Institute, Mumbai, India Shivam Cement (P) Ltd Venus Group of Companies Sika India

• ALOS-2 mission of the Japanese Aerospace Exploration Agency (JAXA)
• Applied Technical Council ATC 40, California, USA
• American Concrete Institute
• American Society of Civil Engineers
• Aydan and Ohta, 2011; Aydan 2007, 2012
• Badan Lal Nyachhyon, Hunting Dangerous Buildings, 2008
• Federal Emergency Management Agency
• International Building Code, 2012
• Jean Ampuero, California Institute of Technology, USA
• Kathmandu Valley Earthquake Risk Mapping Project, UNDP, 1997
• Katsuichiro Goda, Department of Civil Engineering, University of Bristol, Bristol, UK and et el
• National Forum for Earthquake Safety
• Nepal National Building Code 1994 and 2009
• Recommendation for Update of Nepal National Building Code 1994, Earthquake Risk Recovery and Rehabilitation Project, UNDP/ ERRRP-Project: NEP/07/010, Multi Disciplinary Consultants (P) Ltd., 2009.
• United States Geological services
• Various internet sources.

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