Stochastic discrete event simulation for government assisted owner driven participatory housing recovery modeling: Application to 2015 Gorkha earthquake sequence, Nepal

Abstract

We develop and implement a Stochastic Discrete Event Simulation (SDES) algorithm to model the housing recovery trajectory after an extreme event. The algorithm models discrete events and their underlying uncertainties in each construction phase. Specifically, the algorithm is developed for the Government Assisted Owner Driven (GAOD) reconstruction system to simulate long-term recovery trajectory. SDES, as a flexible modeling approach, can simulate any housing recovery scenario that follows phased reconstruction. The 2015 M 7.8 Gorkha earthquake sequence in Nepal is considered the extreme event, with 796,245 buildings requiring reconstruction. We present some recovery trajectories from severely hit, crisis hit, and earthquake hit parishes, comparing them with the actual reconstruction progress. We also assess quality and improvement of reconstructed buildings using seismic fragility functions, compared to pre-earthquake constructions. Housing recovery uncertainties are dissected in relation to reconstruction pace. We conclude that the vast majority of the reconstructed buildings followed the Build Back Better (BBB) approach and missed the opportunity to pursue the Build Back Resilient (BBR) approach due to multifaceted challenges ranging from unclear policies to economic constraints. We critically assess the GAOD vs Owner Driven (OD) recovery framework and conclude that insurance-supported and technically assisted OD approach could be the most suitable model for post extreme event housing recovery.

Keywords

Stochastic modeling / Discrete event simulation / Participatory reconstruction / Housing recovery / Community resilience / Earthquake damage / Reinforced concrete / Stone masonry / Brick masonry / Seismic vulnerability / Gorkha earthquake sequence

References

[1] National Planning Commission. Post disaster needs assessment (PDNA Vol. A and B). 2015. Kathmandu.

[2] Anelli A, Mori F, Mendicelli A, Vona M, Moscatelli M. A large-scale prioritisation to strengthen the resilience of communities in Italian territorial contexts. Struct Infrastruct Eng 2023; 21(9): 1448-64. https://doi.org/10.1080/15732479.2023.2266817.

[3] Hogg SJ. Reconstruction following seismic disaster in Venzone, Friuli. Disasters 1980; 4(2): 173-85. https://doi.org/10.1111/j.1467-7717.1980.tb00271.x.

[4] Hirayama Y. Collapse and reconstruction: housing recovery policy in Kobe after the Hanshin Great Earthquake. Hous Stud 2000; 15(1): 111-28. https://doi.org/10.1080/02673030082504.

[5] Wu JY, Lindell MK. Housing reconstruction after two major earthquakes: the 1994 Northridge earthquake in the United States and the 1999 Chi-chi earthquake in Taiwan. Disasters 2004; 28(1): 63-81. https://doi.org/10.1111/j.0361-3666.2004.00243.x.

[6] Kamel NMO, Loukaitou-Sideris A. Residential assistance and recovery following the Northridge earthquake. Urban Stud 2004; 41(3): 533-62. https://doi.org/10.1080/0042098042000178672.

[7] Zhang Y, Peacock WG. Planning for housing recovery? Lessons learned from hurricane Andrew. J Am Plan Assoc 2010; 76(1): 5-24. https://doi.org/10.1080/01944360903294556.

[8] Rathfon D, Davidson R, Bevington J, Vicini A, Hill A. Quantitative assessment of post-disaster housing recovery: a case study of Punta Gorda, Florida, after Hurricane Charley. Disasters 2013; 37(2): 333-55. https://doi.org/10.1111/j.1467-7717.2012.01305.x.

[9] Green R, Bates LK, Smyth A. Impediments to recovery in New Orleans’ upper and lower ninth ward: one year after Hurricane Katrina. Disasters 2007; 31(4): 311-35. https://doi.org/10.1111/j.1467-7717.2007.01011.x.

[10] Mannella A, Di Ludovico M, Sabino A, Prota A, Dolce M, Manfredi G. Analysis of the population assistance and returning home in the reconstruction process of the 2009 L’aquila earthquake. Sustainability 2017; 9(8): 1395. https://doi.org/10.3390/su9081395.

[11] Di Ludovico M, Prota A, Moroni C, Manfredi G, Dolce M. Reconstruction process of damaged residential buildings outside historical centres after the L’Aquila earthquake: part I-“light damage” reconstruction. Bull Earthq Eng 2017; 15(2): 667-92. https://doi.org/10.1007/s10518-016-9877-8.

[12] Di Ludovico M, Prota A, Moroni C, Manfredi G, Dolce M. Reconstruction process of damaged residential buildings outside historical centres after the L’Aquila earthquake: part II-‘heavy damage’ reconstruction. Bull Earthq Eng 2017; 15(2): 693-729. https://doi.org/10.1007/s10518-016-9979-3.

[13] Comerio MC. Housing recovery lessons from Chile. J Am Plan Assoc 2014; 80(4): 340-50. https://doi.org/10.1080/01944363.2014.968188.

[14] Tena-Colunga A. The recovery process of housing in Mexico City 7+ years after the 2017 Puebla-Morelos earthquake. Resilient Cities Struct Sep. 2025; 4(3): 67-98. https://doi.org/10.1016/j.rcns.2025.08.002.

[15] Basaglia A, Aprile A, Spacone E, Pel`a L. Assessing community resilience, housing recovery and impact of mitigation strategies at the urban scale: a case study after the 2012 Northern Italy Earthquake. Bull Earthq Eng 2020; 18(13): 6039-74. https://doi.org/10.1007/s10518-020-00919-8.

[16] Cimellaro GP, Renschler C, Reinhorn AM, Arendt L. Peoples: a framework for evaluating resilience. J Struct Eng 2016; 142(10): 04016063. https://doi.org/10.1061/(asce)st.1943-541x.0001514.

[17] Li Y, Dong Y, Frangopol DM, Gautam D. Long-term resilience and loss assessment of highway bridges under multiple natural hazards. Struct Infrastruct Eng 2020; 16(4): 626-41. https://doi.org/10.1080/15732479.2019.1699936.

[18] Tena-Colunga A. Seismic performance and recovery of medical infrastructure in Mexico City related to the September 19, 1985 and 2017 earthquakes. Int J Disaster Risk Reduct 2024; 113: 104886. https://doi.org/10.1016/j.ijdrr.2024.104886.

[19] Bruneau M, et al. A framework to quantitatively assess and enhance the seismic resilience of communities. Earthquake Spectra 2003; 19(4): 733-52. https://doi.org/10.1193/1.1623497.

[20] Cimellaro GP, Reinhorn AM, Bruneau M. Performance-based metamodel for healthcare facilities. Earthq Eng Struct Dyn 2011; 40(11): 1197-217. https://doi.org/10.1002/eqe.1084.

[21] Cimellaro GP, Cardoni A, Reinhorn A. Modelling infrastructure interdependencies and cascading effects using temporal networks. Resilient Cities Struct Sep. 2024; 3(3): 28-42. https://doi.org/10.1016/j.rcns.2024.05.002.

[22] De Iuliis M, Khaghanpour-Shahrezaee R, Cimellaro GP, Khanmohammadi M. Fuzzy-based approach to quantify the downtime of buildings in developing countries. Resilient Cities Struct 2024; 3(1): 1-19. https://doi.org/10.1016/j.rcns.2023.11.001.

[23] De Iuliis M, Kammouh O, Cimellaro GP. Measuring and improving community resilience: a fuzzy logic approach. Int J Disaster Risk Reduct 2022; 78: 103118. https://doi.org/10.1016/j.ijdrr.2022.103118.

[24] Iervolino I, Giorgio M. Stochastic modeling of recovery from seismic shocks. In: 12th International Conference on Applications of Statistics and Probability in Civil Engineering, ICASP 2015; 2015.

[25] Cardoni A, Zamani Noori A, Greco R, Cimellaro GP. Resilience assessment at the regional level using census data. Int J Disaster Risk Reduct 2021; 55: 102059. https://doi.org/10.1016/j.ijdrr.2021.102059.

[26] Chang SE, Shinozuka M. Measuring improvements in the disaster resilience of communities. Earthq Spectra 2004; 20(3): 739-55. https://doi.org/10.1193/1.1775796.

[27] Kammouh O, Dervishaj G, Cimellaro GP. Quantitative framework to assess resilience and risk at the country level. ASCE ASME J Risk Uncertain Eng Syst A Civ Eng 2018; 4(1): 04017033. https://doi.org/10.1061/ajrua6.0000940.

[28] Bowden MJ, Haas JE, Kates RW. Reconstruction following disaster. 1977. Cambridge, Massachusetts.

[29] Alisjahbana I, Kiremidjian A. Modeling housing recovery after the 2018 Lombok earthquakes using a stochastic queuing model. Earthq Spectra 2021; 37(2): 587-611. https://doi.org/10.1177/8755293020970972.

[30] Federal Emergency Management Agency (FEMA) . Hazus-MH MR5 user manual. Multi-hazard loss estimation methodology: earthquake model. 2010. Washington DC.

[31] Gautam D, Fabbrocino G, Santucci de Magistris F. Derive empirical fragility functions for Nepali residential buildings. Eng Struct 2018; 171: 617-28. https://doi.org/10.1016/j.engstruct.2018.06.018.

[32] Gautam D. “Past and future of earthquake risk reduction policies and intervention in Nepal”. Impacts and Insights of the Gorkha earthquake 2018: 173-82. https://doi.org/10.1016/B978-0-12-812808-4.00007-9.

[33] Gautam D, Rodrigues H, Bhetwal KK, Neupane P, Sanada Y. Common structural and construction deficiencies of Nepalese buildings. Innov Infrastruct Solut 2016; 1(1): 1. https://doi.org/10.1007/s41062-016-0001-3.

[34] Gautam D, Chaulagain H. Structural performance and associated lessons to be learned from world earthquakes in Nepal after 25 April 2015 (Mw 7.8) Gorkha earthquake. Eng Fail Anal 2016; 68: 222-43. https://doi.org/10.1016/j.engfailanal.2016.06.002.

[35] Barbosa AR, et al. Performance of medium-to-high rise reinforced concrete frame buildings with masonry infill in the 2015 Gorkha, Nepal, earthquake. Earthq Spectra 2017; 33(1): 197-218. https://doi.org/10.1193/051017EQS087M.

[36] Gautam D. Observational fragility functions for residential stone masonry buildings in Nepal. Bull Earthq Eng 2018; 16(10): 4661-73. https://doi.org/10.1007/S10518-018-0372-2.

[37] Gautam D, Rodrigues H. Seismic vulnerability of urban vernacular buildings in Nepal: case of Newari construction. J Earthq Eng 2021; 25(1): 43-64. https://doi.org/10.1080/13632469.2018.1498411.

[38] National Reconstruction Authority (NRA) . Five years of reconstruction (2015-2020). 2020. Kathmandu.

[39] Gautam D. Assessment of social vulnerability to natural hazards in Nepal. Nat Hazards Earth Syst Sci 2017; 17(12): 2313-20. https://doi.org/10.5194/nhess-17-2313-2017.

[40] Cardoni A, Cimellaro GP. The role of reinforced concrete roofs in the seismic performance of masonry buildings. J Build Eng 2020; 28: 101056. https://doi.org/10.1016/j.jobe.2019.101056.

[41] Bhattacharya S, Nayak S, Dutta SC. A critical review of retrofitting methods for unreinforced masonry structures. Int J Disaster Risk Reduct 2014; 7: 51-67. https://doi.org/10.1016/j.ijdrr.2013.12.004.

[42] Yavartanoo F, Kang THK. Retrofitting of unreinforced masonry structures and considerations for heritage-sensitive constructions. J of Buil Enginee 2022; 49: 103993. https://doi.org/10.1016/j.jobe.2022.103993.

[43] Grunthal G. European macroseismic scale 1998 (EMS-98). 1998. Luxembourg Accessed: Aug. 16, 2023. [Online]. Available: https://www.franceseisme.fr/EMS98_Original_english.pdf.

[44] Giovinazzi S, Lagomarsino S. A macroseismic method for vulnerability assessment of buildings. In: Proceedings of the 13th World Conference on Earthquake Engineering; 2004. Vancouver.

[45] Lagomarsino S, Giovinazzi S. Macroseismic and mechanical models for the vulnerability and damage assessment of current buildings. Bull Earthq Eng 2006; 4(4): 415-43. https://doi.org/10.1007/s10518-006-9024-z.

[46] Housing Recovery and Reconstruction Program, “ Housing typologies: earthquake affected districts,” Kathmandu, 2018.

[47] Zanini MA, Hofer L, Faleschini F. Reversible ground motion-to-intensity conversion equations based on the EMS-98 scale. Eng Struct 2019; 180: 310-20. https://doi.org/10.1016/j.engstruct.2018.11.032.

[48] Gautam D, Rupakhety R, Adhikari R, Shrestha BC, Baruwal R, Bhatt L. Seismic vulnerability of Himalayan stone masonry: regional perspectives, Masonry construction in active seismic regions 2021: 25-60. https://doi.org/10.1016/B978-0-12-821087-1.00014-4.

[49] Aung WY, Gautam S, Gautam D. Damage mechanisms and seismic vulnerability of building structures following the 2025 M 7.7 Mandalay earthquake sequence, Myanmar. Eng Fail Anal 2025; 180: 109849. https://doi.org/10.1016/j.engfailanal.2025.109849.

[50] Hofmann SZ. Build back better and long-term housing recovery: assessing community housing resilience and the role of insurance post disaster. Sustainability 2022; 14(9): 5623. https://doi.org/10.3390/su14095623.

[51] Gautam D, Thapa S, Pokhrel S, Lamichhane S. Local level multi-hazard zonation of Nepal. Geomat Nat Hazards Risk 2021; 12(1): 405-23. https://doi.org/10.1080/19475705.2021.1879941.