2023 Herat Afghanistan Earthquake Preliminary Shelter and Housing Response
On Oct 8th, 2023, Miyamoto’s first assessment team was deployed to conduct a rapid assessment of the affected area. The earthquake affected 11 villages in the Zinda Jan district of Herat province. It is estimated that more than 100,000 people were exposed to high-ground intensity. The epicenter was about 40 kilometers northwest of Herat city and brought significant causalities in these villages.
EARTHQUAKE IMPACT METRICS
The following current statistics are per the Afghanistan National Disaster Management Authority (ANDMA).
- The demographics in this region are characterized by an average family size of six individuals, with four families residing on average in each compound.
- Families are living inside compound walls as tall as 3 meters. Walls provide a very important social structure, such as privacy for women and girls.
- Many of the structures are built with clay.
Quality of materials and work
Foundation and stem walls
- It was observed during the assessment that both compound and house/room walls built with clay have no stone foundation and stone stem parts (see Figure 1). It was also heard during an interview with villagers that they cannot afford stones for foundation and stem/plinth walls, although some stone sources were located at an average distance of 7-10 km. Stone foundations at the bottom of the clay walls are critical for moisture protection mitigating against deterioration, which increases vulnerability to earthquake damages.
- It was observed that approximately 90% of the walls in these structures have been constructed using materials like mud cob or Morachini (Pakhsa), with the remaining 10% incorporating adobe. Notably, in a significant number of cases, mud plaster has been applied to these walls. In addition to this, the soil sources were observed in the villages, and enough amount of clay was confirmed after field tests (Sigar and Wash) were conducted.
- The following structural deficiencies were observed:
- The local skills for the construction of mud vernacular structures are limited; this was observed in the low quality of works with several failures. For instance, it seemed that the soil was not soaked for enough time in order to be sufficiently saturated with water.
- In addition, regarding the thickness of the walls, in some cases, the lower part was smaller than the upper part. This can reduce stability during earthquakes.
- Different molds were used for brick production. Thus, the use of bricks with different sizes was observed in a single wall, which can create problems in jointing.
- In some walls, cement blocks were adjacent to the adobe.
- For exterior room walls, cement blocks were used, while adobe was used on the inner side of the rooms (See Figure 2).Lintel over openings were made of adobe arches, which makes these structures vulnerable to earthquake damage/collapse.
- Approximately 95% of the houses in the affected area feature domed roofs constructed from traditional materials, such as adobe.
- The use of adobe in mud mortar for dome roofing is common in this area.
- Additionally, the use of large-sized mud bricks (30 x 30 x 20 cm) with mud mortar poses a challenge in terms of cohesion between them.
- The thickness of such roofs reached 40 cm in some cases. This thick material is heavy and creates a high seismic mass, which induces higher seismic demand for walls.
- The villagers stated that the domed roof construction process starts from all four sides of the rooms simultaneously without any shuttering under them. Thus the failure of such roofs is very common even during the construction process (see Figure 3). This may present seismic risks, as it can easily disintegrate during earthquakes and fail during energy dissipation.
- In Sarbuland village, the villagers reported that 36 people were killed by failure of dome roofs, while few injuries were reported by the failure of flat roofs.
- 5% of roofs are flat roofs constructed from steel I-beams with bricks serving as infill between the beams and stucco as cohesion materials. These structures did not sustain major damages in the earthquake, and no fatalities occurred.
With the impending arrival of the harsh winter, it becomes increasingly imperative to ensure the provision of safe shelters for the affected population, not only before the winter sets in but also as a lasting solution beyond the winter months. In this regard, the following actionable recommendations are provided for both immediate and transitional responses:
1.Immediate Response: It is of utmost importance to swiftly establish temporary warm “bunkers” to offer refuge for the affected residents. These bunkers are often found in southeast region during the war. It is built by digging 2 meters into the ground and build 1-meter-high clay walls. The roof will be composed of a flat clay roof supported by steel beams, these temporary shelters will serve as a vital lifeline, providing a safe and warmer environment for people to weather the freezing winter. These bunkers were built after the 2022 earthquake in the southeast region before winter. It’s crucial to note that the winter is expected to make its presence felt by mid-November, underlining the urgency of this short-term intervention. The villagers reported that this area is prone to heavy winds that tents cannot withstand. This southeast vernacular technology can be rapidly adapted into local populations. This was extensively discussed with affected populations, and they agreed on the approach.
2.Mid-Term Solution:Based on the field observation and interviews with villagers, the houses are not repairable due to the low quality of construction. Thus, we recommend:
- Enhance the technical capacity of the local community. It should be brought up to similar capacity as the southeast region.
- Paskha/Morichini/cob or Khama Khashta/adobe for walls and flat roofs made of steel I-beams with clay roofs are safe for earthquake construction and can be adapted here.
- If domed roofs are used, a thorough investigation is required to assess their earthquake performance.
- Capping for Paskha and Khama Khashta walls is recommended to reduce the risk of wall erosion.
- The villagers asked for compound walls around their shelters in order to ensure women’s privacy.
VILLAGE SITE VISITS
The team visited six villages that were significantly affected by the earthquake. The information from site observations and interviews is stated below: