A field assessment for intervention strategies
By Deben Bachaspatimayum
6.7 Richter scale earthquake rocked everyone out of their beds in the wee hours of 4th Jan 2016. Vehicular rush from all directions headed for towards Tamenglong where the epicentre was located in a remote hills around 17 kms from Noney on the NH-53 and some villages easily accessible from the NH. Noney is about 42 kms from Imphal Tamenglong is western hill district of Manipur adjoining Silchar plains of Assam in the west and Paren district of Nagaland in the north. The district is predominantly inhabited by Rongmei tribes. The district has a population of 140, 561 (2011 Census) comprising 72,371 male & 68,280 female with population density of 32 persons in a total areas of 4,391 sq.km. The district is administered from Tamenglong HQ, around 145 kms from Imphal through five sub-divisional /TD Block offices. Nungba and Tamenglong blocks experienced the major impacts of the quake. The entire western hill tracts, reportedly, falls under the Seismic zone V. The district is targeted with multiple mega projects relating to Trans Asian roads and railways, mega dams and petroleum exploration which are extensively affecting natural environment and traditional life of the people. Geological survey including test drilling works has been going all along the NH for the last 5-10 years.
Impacts on houses
First hand information from the fields show Mud Block-Wall Houses (MWH) received extensive damages compared to other types of houses in the villages. Irrespective of extent of damage: partial or completely fallen, the people had relocated themselves in single room kitchen (which are built in traditional style as an annex house) in the neighbourhood safer houses for the fears of falling and getting crushed anytime in the face of impending aftershocks. Cracks on grounds cutting across the NH, house floors and hill tops, and 400 KV towers and along line the oil exploration survey appeared. These cracks were widening 5-6 inches and deepening 4-5 ft at several places causing serious fears and concerns of possible major landslides by the onset of rainy season. Although, there was no immediate emergency humanitarian crisis situation further delay in reconstructing all the MWH (partially or fully damaged) in particular, the cramped living conditions in single kitchen rooms or in neighbourhood is going to soon compromise children’s education after winter break, women health and privacy in the long run.
Though detailed impacts on the physical, social, economic and psychological aspects on the lives of the people and the natural environment is yet to be assessed, comprehensively, this report has special focus on the damages of the houses and suggestions for appropriate supports based on local initiatives.
Based on the field assessment carried out in three villages namely; Noney, Nungba and Ruangdai, and information collected from Village Authorities from another eight villages namely; Rengpang, Sangrung (Khongshang), Taubam, Kambiron under Nungba sub-division, Sungrungpeng, Keikao, Inriangluang and Dailong villages under Tameglong sub-division and Sub-Divisional office of Nungba between 5th and 7th Jan 2016 following observations are made.
Entire families in all the MWH houses (20-30% approx) are partially and fully damaged. People had vacated and lived abnormal normal life having to huddle in available single-room traditional kitchen houses in the annex
Those who were injured in these places where taken care by Govt and Pvt. Healthcare services
Although the shocks have disrupted normal life there is no indication that immediate livelihood of the people is threatened as no food grain stores and normal water supplies are intact and where steam water was affected Pvt. Companies were making up the deficiency.
Although normal transport to all affected villages was not affected disruptions in the telecommunications and power supply occurred due to impacts on some towers and power lines
People, in general, continue to live normal life all other houses (approximately, 70-80%) despite the impending dangers/ fears of aftershocks and uncertainties around it was felt
Impacts on Mud-Wall Houses or MWH
Traditional MWH (20-30% approx), locally known as Leirung-kai have been popular choice for many across villages who cannot afford RCC/Brick-Wall houses (RBH). Such house is not indigenous to Rongmei tribe. Reasons for choosing MWH (which takes time and intensive labour to build) are; cool in summer and warm in the winter, and durability – last as long as 100 years, said the respondents. Other types of houses like; RBH (5-10%), the semi-pucca houses with Bamboo mesh walls with mud-plaster or BMP (40-60%)) and the traditional Bamboo Mesh walled houses with thatch or tin roof or BMH (5-10%) escaped the quake without a serious scratch although cracks in the ground below did not spare any!
Damages suffered by the Mud Block-Wall Houses (MWH) varied in degrees ranging from simple vertical crack lines in the corners to complete falling off of the walls and crumbling blocks. Age of these houses ranged between 1 year fresh to 15 years old. Around 20-30 damaged houses in 4 villages namely; Noney, Nungba, Ruangdai and Khongshang were inspected. Closer look and physical examination of the fallen pieces of mud blocks give clues to different qualities of the soil used from village to village and varying strengths of bamboo stripes found between the layers of mud-blocks. Sandy soil with less bamboo stripes works between horizontal mud-block layers without wall plasters (mud+cowdung) easily fell apart by the quake impacts compared to others in the different village where soil was clayey and more bamboo stripes were used to hold the horizontal layers of mud blocks and corners together. All the MWH had cracks in the corner but those in which bent bamboo angles were used to hold walls together in the corner and good quality plasters on the walls had the minimum cracks in the corner and walls were fairly intact.
Descriptions of damaged MWH
22 MWH houses were inspected in Nungba and Ruangdai villages under Nungba sub-division but the data given below are only for 15 houses from Ruangdai village. MWH measures a foot uniformly in width and stands 6-7 ft in height. Layers of Mud Blocks measuring 1ft x 1 ½ ft x 2ft are mounted along the length of walls with 1 or 2 bamboo strips running between the horizontal layers over a number of days to allow previous layers to dry enough to hold fresh mud layers. No blocks are used. Mud block walls are plastered with a mixture of fine sand and cowdung and in some houses, walls had paints.
Local innovation in the MWH houses:
From the above descriptions of damages on the Mud Block Wall Houses it is observed that the strength and life of MWH houses depend on type of mud used, quality of plaster works and strength of bamboo stripes network running between along the horizontal layers and the manners in which these bamboo stripes met / joined at the corners to hold the walls together at the right angles. It seemed no standard quality of mud mix, plaster and bamboo networks was maintained which may have caused the MWH houses getting varying degrees of damages on them.
Locally available mud which contained varying compositions of clay and sand was used in building at different housing sites. Some houses had strong plasters on the walls and paintings done and others had very poor to plaster, peeling off and exposing the mud blocks. Numbers, size and length of bamboo stripes used between the horizontal layers and at the corner joints between walls also differ from one house to another. Investigators found out most extensively damaged houses had ends of bamboo stripes lying one over the other at the corners where two walls meet at right angle corners and few other which had minor damage had long half bamboo stripes, at least two or three in numbers adding to strength, running between horizontal layers bent along the right angle corners to further run along the same layers of the adjoining walls. One house (which belonged to the Pastor of the village Church in Ruangdai) where bent bamboo stripes were used at the right angle corners to hold adjoining walls together with good quality plasters and paintings done on the walls had only minor cracks at the corners leaving the house intact in shape and form. Members of the house had no fear of sleeping in the house after the shock. In conclusion, the use of good quality mud, plaster works and use of bent bamboo stripes in the corner, which may be local innovations, resisted the damaging impacts of 6.7 Richter scale earthquakes few kms away from the epicentre.
Intervention strategies for reconstruction
Given that fact the mud-bamboo-plaster houses are environment friendly, sustainable based on locally available materials and skills, economic and durable intervention strategies for reconstruction of earthquake resistant houses must also be guided by building on local innovations and materials with some scientific /technological inputs to improve quality of mud mixtures and structures and strengths of bamboo stripes networks. Intervention based on the above considerations will encourage local innovations, initiatives and value addition to local resources by which dependency on external supplies of artificial construction materials and compounding problems of repair and maintenance will be reduced. For these environmental, social and economic considerations the following activities may be considered without compromising immediate needs of shelter which also demands some urgency so the works of reconstruction completes before the onset of academic session and also the seasonal rains:
Field assessment of damage MWH and those of lower-income / poor families who may need such houses in all the listed villages where ActionAid will work
Where people are already making temporary shelters it must be encouraged so all those who have not started also have temporary shelters while initiatives for reconstruction of houses take off
Local brigades/ Work Force Team of skilled labourers/housemakers, especially for women-headed households and others who have no able bodies, may be organized and engaged in making temporary shelters on wage labour basis
Organize local skilled and experienced mud wall house makers to study and development their own theory and models of earthquake resistant models based the recent experiences by providing financial assistance
In each village skilled, experienced and knowledgeable persons may be identified and assigned to study the damage and come up with theoretical and practical model of earthquake resistant mud-wall house
Experts in the field of mud and bamboo house construction may be engaged to study the local construction materials and provide the right quality mixtures of mud composition for wall construction, structural designs of bamboo networks, and plaster works that is earthquake resistant
Based on expert findings and local experiences joint team initiative of external experts and local skilled persons may develop a model house in each village on shared cost basis (labour and material as local contribution with part financial assistance). This may be worked out once a model is created
Form local brigades of Work Force Team of house-makers who may be tasked to rebuild all damaged houses and also for those belonging to lower income group/poor desirous of building MWH, in time-bound manners with part financial support that pays for their skill labour
This report is based on two days field assessment works conducted by a joint team of ActionAid Association, Regional Office based in Guwahati and Senior Research Fellow of Volunteers for Village Development on 6-7th Jan 2016.