Disaster mitigation refers to a series of efforts carried out before a disaster occurs to reduce potential losses, including casualties and infrastructure damage. In coastal areas, mitigation is especially crucial, as these zones are the most vulnerable to tsunami hazards (Diposaptono 2011). Mitigation strategies in coastal regions must consider the geophysical and socio-economic characteristics of local communities to ensure that the approaches implemented are both participatory and adaptive (Haryani 2016; Wibowo et al. 2019). Government Regulation of the Republic of Indonesia No. 64 of 2010 states that disaster mitigation must be implemented through both structural and non-structural approaches. Structural approaches include physical infrastructures such as breakwaters, evacuation routes and signs and emergency shelters. Meanwhile, non-structural approaches focus on enhancing community capacity through education, training and the strengthening of early warning systems (Pemerintah 2010).

However, effective mitigation cannot rely solely on modern technology. In the context of coastal communities, indigenous knowledge has long been an integral part of natural early warning systems, self-evacuation practices and post-disaster social solidarity mechanisms (Hamid et al. 2021; Hiwasaki, Luna & Shaw 2014; Simarmata & Indrawati 2022; Syarif, Hendra & Saputro 2023).

Regional resilience in facing disasters is shaped by a combination of structural and non-structural factors. Coastal resilience can be strengthened through local adaptations that take into account the social and cultural capacities of the community. These include trust in natural signs, the role of traditional leaders as mobilisers and inherited traditions that reinforce community awareness (Chowdhooree 2019; Sarthi & Michael 2025; Yance et al. 2024).

The Ministry of National Development Planning (Bappenas) and the National Disaster Management Agency (BNPB) have also emphasised the importance of disaster risk reduction (DRR)-based development strategies that are integrated with local socio-cultural systems to ensure greater adaptability and inclusiveness (BNPB 2020). This approach is crucial to ensure that mitigation strategies are not solely dependent on physical infrastructure but also incorporate the values and lived experiences deeply embedded in community life.

The development of infrastructure such as breakwaters and evacuation routes is a crucial component of structural mitigation strategies. However, such infrastructure will not function optimally without a solid understanding of local contexts (Kusumasari & Alam 2012). While breakwaters can reduce the intensity of tsunami waves, the effectiveness of evacuation is largely determined by the community’s ability to recognise and respond to warnings both formal and informal (Hirmawan & Anisah 2018). Local wisdom, such as the use of natural evacuation paths (e.g. footpaths leading to higher ground), the designation of places of worship or traditional halls as emergency gathering points and the interpretation of natural sounds as danger signals, serves as a complement to structural mitigation systems (Kusuma, Ramadhan & Suryanda 2020; Mare, Angin & Rahmawati 2021).

Spatial-based risk mapping is an essential tool for identifying tsunami-prone areas and establishing evacuation zones (Purwanto et al. 2017). However, for such planning to be effective, it must be aligned with the spatial patterns and cultural values of local communities. Evacuation routes that conflict with local customs or beliefs are often ignored or underutilised. In the context of South Lampung, many coastal communities possess a collective historical experience of disasters and have inherited knowledge systems passed down through generations. Therefore, the ideal mitigation strategy integrates modern mapping technologies with local knowledge and existing customary social structures (Hiwasaki et al. 2014).

Disaster mitigation based on indigenous knowledge is a strategic approach that integrates cultural values, traditional knowledge and social norms in efforts to prevent and reduce disaster risks. The culturally rich Indonesian society has long practiced various forms of indigenous knowledge, both in ecological aspects, such as earthquake-resistant house designs in Minangkabau, Nias and Acehnese communities, and in social systems, such as the tane’ olen [customary forest] concept among the Dayak people or tsunami warnings through the ‘smong’ tradition in Simeulue. These forms of indigenous knowledge reflect a life philosophy in harmony with nature and have been passed down across generations, proving that simple yet meaningful local practices can offer real protection from natural hazards (Aldiansyah 2021). Therefore, the preservation and strengthening of indigenous knowledge are crucial to developing sustainable, community-based disaster mitigation strategies.

Indigenous knowledge also manifests in adaptive behaviours towards the environment. Such wisdom can be transferred to other communities with similar characteristics and disaster contexts. It serves as a vital safeguard in improving community preparedness for natural hazards like tsunamis (Dewi & Sihombing 2022). Haryani’s research underscores the importance of empowering coastal communities to design and implement mitigation strategies aligned with their socio-cultural values (Haryani 2016; Zalmansyah et al. 2023). By positioning communities as subjects rather than objects in disaster planning, this approach fosters long-term risk awareness and enhances community resilience from within.

Studies conducted across several island nations in Asia show that integrating local knowledge with modern warning systems significantly improves community preparedness for hydrometeorological disasters and tsunamis (Hiwasaki et al. 2014). Communities that are given the space to utilise and develop their indigenous knowledge exhibit faster and more accurate responses when disasters occur. In Simeulue, Aceh, the community preserves and transmits the smong narrative, a local term for tsunami, through songs, folklore and rituals (Kurniasih, Marin & Setyawan 2020; Rahman, Sakurai & Munadi 2017, 2018). This knowledge proved life saving during the 2004 tsunami, making Simeulue one of the regions with the lowest fatality rate despite its proximity to the epicentre.

Based on the findings above, it is evident that indigenous knowledge is not merely a complement but the core of sustainable disaster mitigation strategies. The integration of modern scientific systems with local practices can create mitigation frameworks that are more adaptive, contextual and resilient, especially in coastal areas like South Lampung. Research in Papua New Guinea and the Solomon Islands shows that traditional knowledge has strategic value in DRR systems. Communities in these regions recognise natural signs such as changes in sea colour, seabird behaviour and ground tremors as early warnings, passed down through oral traditions (Kusuma et al. 2020; Mare et al. 2021; Mercer et al. 2010). These studies affirm that when traditional knowledge is integrated with scientific systems and modern technologies, mitigation effectiveness increases significantly, particularly in remote areas with limited formal infrastructure.

Meanwhile, research in Japan reveals that locally rooted preparedness cultures, especially through traditional evacuation routes and community-led disaster training, play a key role in reducing casualties during tsunamis (Shaw 2014). Coastal communities in Japan do not solely rely on high technology but consistently maintain routine evacuation drills, narrative-based disaster history markers and spatial planning based on traditional practices. This research demonstrates that the success of mitigation is not solely determined by technological sophistication but also by consistency, community education and the sustainability of local culture.

Ethical clearance to conduct this study was obtained from the Institute for Research and Community Service of Sumatra Institute of Technology (No. [2593/IT9.2.1/PT.01.05/2025]).

Breakwaters are widely implemented as structural measures in tsunami-prone coastal regions. In Kalianda and Rajabasa, breakwaters have been constructed since 2022 through central government funding (APBN). Field observations (Figure 1 and Figure 2) indicate that approximately 65% of high-risk shoreline areas in Kalianda and 52% in Rajabasa are directly protected by breakwaters, reducing wave energy and mitigating potential damage (Firdaus et al. 2023).

Beyond their physical function, local communities perceive breakwaters as symbols of protection, integrating cultural narratives such as ‘coastal guardians’ into their use (Douvinet et al. 2024; Rahman et al. 2018; Triana 2017). This demonstrates the synergy between infrastructure and local cultural values.

Mitigation facilities, including evacuation signs, designated evacuation routes and assembly points, are essential components of effective disaster response strategies. Field observations in Kalianda and Rajabasa districts indicate that most evacuation signs comply with the Indonesian National Standard (SNI 7743:2011) (BSN 2011), ensuring clear guidance during emergencies. Several villages have reinforced key evacuation routes with concrete pavements, enhancing accessibility for vulnerable groups such as the elderly, children and pregnant women (Figure 3). Despite these improvements, disparities remain, as some routes are still unpaved or covered with gravel, which can impede rapid evacuation during a tsunami event. This situation underscores the critical role of community involvement in planning, maintaining and evaluating evacuation infrastructure. Local knowledge from past disasters informs the placement and usability of evacuation routes, while community participation ensures that infrastructural improvements align with cultural practices and local environmental conditions.

Evacuation sites are generally open fields situated on higher terrain, such as the slopes of Mount Rajabasa. In several villages, residents supplement formal assembly points by utilising traditional halls [balai adat] or community-owned land as emergency gathering locations (Douvinet et al. 2024). These practices highlight the importance of social capital in disaster mitigation, demonstrating how local communities actively compensate for gaps in formal infrastructure, strengthen preparedness and reinforce collective resilience (Mercer et al. 2010).

Effective tsunami mitigation in Kalianda and Rajabasa sub-districts extends beyond physical infrastructure, requiring the integration of cultural values and local knowledge into disaster management strategies. Coastal communities continue to rely on traditional knowledge systems, including the interpretation of ocean sounds, wind patterns and animal behaviour, as early indicators of impending hazards. Additionally, orally transmitted narratives about historically recognised ‘safe zones’ guide residents during evacuations, ensuring timely and contextually informed decision-making (Rahman et al. 2017, 2018; Trogrlić et al. 2022).

Beyond these cognitive tools, social practices such as cooperation [gotong royong], adherence to traditional leadership structures and strong communal bonds function as critical social capital that reinforces community-based disaster response. For example, collective decision-making and voluntary mobilisation during emergencies enhance both the reach and effectiveness of mitigation measures.

The integration of local systems with formal disaster management mechanisms exemplifies the principles of the community-based disaster risk reduction (CBDRR) approach, which emphasises active community participation across the mitigation cycle from planning and preparedness to response and recovery (Firdaus et al. 2023; Hiwasaki et al. 2014; Shaw 2014). This approach ensures that infrastructural interventions, such as breakwaters, evacuation routes and assembly points, are not only technically sound but also socially accepted, culturally relevant and sustainably maintained by the community.

Figure 4 presents a composite vulnerability and mitigation map generated using ArcGIS, which visualises the spatial distribution of breakwaters, evacuation routes, signage and gathering points in Kalianda and Rajabasa districts (Lin & Lee 2025). This map not only depicts the existing disaster mitigation infrastructure but also identifies areas that still require intervention, serving as both a technical tool and a decision-support resource.

The distribution of mitigation facilities in Kalianda is relatively uniform, reflecting the district’s flatter topography and greater accessibility. In contrast, Rajabasa’s hilly and less accessible terrain results in a more uneven placement of infrastructure. Notably, many evacuation points were located based on community input regarding traditionally recognised ‘safe zones’, demonstrating the integration of local knowledge with spatial analysis. This collaboration between scientific mapping and indigenous knowledge strengthens both the relevance and usability of mitigation plans.

The presence of disaster-related infrastructure has enhanced the effectiveness of community response. Socially, residents can conduct rescue and evacuation operations more efficiently, while vulnerable groups, including pregnant women, the elderly, children and people with disabilities, benefit from safer and more accessible evacuation routes and assembly points (Douvinet et al. 2024).

Moreover, mitigation facilities extend their benefits beyond administrative boundaries. Communities in adjacent areas with easier access to Kalianda or Rajabasa can utilise breakwaters, evacuation routes and assembly points, enhancing regional resilience. The breakwaters also provide physical and economic protection, reducing potential damage to residential areas, public infrastructure and social facilities from tsunami waves or tidal inundation.

Overall, the vulnerability map reflects a synergistic approach where spatial analysis, structural mitigation and local knowledge converge, illustrating the critical role of community participation in designing effective and contextually appropriate disaster mitigation strategies.

The findings of this study demonstrate that tsunami disaster mitigation strategies in Kalianda and Rajabasa sub-districts extend beyond conventional structural measures such as breakwaters, evacuation signs and designated evacuation routes. These strategies are deeply reinforced by indigenous knowledge, which encompasses knowledge, values and social practices that have been passed down across generations and actively maintained through the leadership of traditional and community figures in coastal villages.

A key element of this indigenous knowledge is the use of natural signs as early warnings for tsunami hazards. Residents recognise phenomena such as sudden sea retreats, roaring ocean sounds and unusual animal behaviours as critical indicators of impending disasters. While this knowledge is not formally documented, it is transmitted orally by traditional elders, who act as custodians of cultural memory and historical disaster experiences, including the tsunamis of 1883 and 2018 (Douvinet et al. 2024; Fakhriati et al. 2023; Hermans et al. 2022; Jokowinarno 2011; Marhadi et al. 2024; Rahman et al. 2017, 2018).

Traditional and community leaders play an essential role in disseminating this knowledge, particularly through informal channels such as religious gatherings, village meetings and ceremonial events (Benazir et al. 2023; Firdaus et al. 2023). Their authority enables them to mobilise residents during emergencies, with some even organising self-initiated evacuation drills carried out by local youth groups or fishing communities (Fakhruddin & Elmada 2022). In some instances, they even initiate self-organised evacuation simulations conducted by fishing groups or village youth.

Another significant aspect of indigenous knowledge as Indonesian local wisdom is the culture of cooperation [gotong royong], which constitutes a core identity of South Lampung communities. During disasters, this principle manifests as spontaneous assistance to vulnerable populations, such as the elderly, children and pregnant women, collective cleanup of debris and the establishment of temporary shelters. Gotong royong also plays a preventive role, seen in regular maintenance of evacuation routes and community-installed signage (Purwanto et al. 2017; Wialdi et al. 2021). In disaster mitigation, the presence of traditional leaders and the active practice of gotong royong complement formal technical strategies implemented by government agencies. Without these socio-cultural supports, interventions such as evacuation signage, rescue routes and assembly points often face low community acceptance and limited effectiveness (Table 1). Therefore, an integrative and participatory mitigation approach is ideal in South Lampung, combining modern technological and infrastructural measures with local socio-cultural systems to enhance acceptance, sustainability and resilience of disaster mitigation efforts (BNPB 2020; Jokowinarno 2011; Machruf et al. 2020; Rahman et al. 2017).

Traditional leaders hold a highly strategic position within the social structure of coastal communities (Crosweller & Tschakert 2021; Humaedi 2016; Wialdi et al. 2021). Their presence is not only respected as guardians of cultural values but also trusted as moral authorities in collective decision-making, including in disaster management contexts. In the tsunami mitigation practices in Kalianda and Rajabasa sub-districts, traditional leaders fulfil various essential functions that reflect the integration between local knowledge and community-based disaster response (Jokowinarno 2011).

Local adaptive plant species along coastal areas play a crucial role in disaster mitigation and enhancing food security. These plants naturally grow along shorelines, possess strong woody structures and have robust root systems capable of withstanding high winds and large waves, including tsunamis. Key species include mangroves (Rhizophora spp., Avicennia spp., Sonneratia spp.), beach almond (Terminalia catappa), she-oak (Casuarina equisetifolia), Ambon palaka (Sterculia foetida L.), banyan (Ficus benjamina), mahogany (Meliaceae sp.), sea hibiscus (Thespesia populnea), devil tree (Alstonia scholaris) and coconut (Cocos nucifera). Ecologically, these species function effectively as natural wave breakers, air pollutant absorbers, soil stabilisers and oxygen providers.

Beyond ecological benefits, these plants hold significant economic and social value. For instance, mangroves can be utilised in traditional medicine, mahogany serves as raw material for furniture and botanical pesticides and coconut trees provide products such as VCO, coconut fibre and charcoal. Beach almond and she-oak contribute to aesthetic value and habitat provision for local fauna, while some species also serve as alternative food sources, enhancing local food security. Consequently, the utilisation of coastal vegetation should be integrated with environmental conservation and community education efforts, creating synergy between ecological preservation and economic empowerment. Mangrove ecosystems, in particular, have been proven effective in dissipating tsunami energy while supporting sustainable livelihoods for local communities (Alongi 2008; Lin & Lee 2025; Rasyid 2024; Ruiz-Ballesteros 2011).

In addition to bolstering community resilience, local wisdom-based mitigation strategies in Kalianda and Rajabasa sub-districts contribute directly to the sustainability of coastal tourism. The southern coast of Lampung, with destinations such as Kedu Warna Beach, Canti Beach and Rajabasa Mountain Tourism Area, benefits from mitigation infrastructure including breakwaters, evacuation routes and safe assembly points, which provide a sense of security for both tourists and businesses. Furthermore, incorporating indigenous knowledge into disaster mitigation enriches culture-based tourism by showcasing disaster history narratives, traditional rituals and coastal vegetation as part of disaster education tourism programmes (Lin & Lee 2025; Rusmiati, Persada & Hardilla 2023; Tatiyanantakul 2021; Zaidan 2019). These integrative strategies demonstrate that effective disaster mitigation not only safeguards residents but also supports the development of a resilient and sustainable tourism economy.