When Mount Semeru erupted in East Java on 19 November 2025, hot clouds travelled more than 13 kilometres from the summit, and the volcano’s alert status rose to its highest level within hours. Roads closed, homes and public facilities were damaged, and hundreds of residents moved to safety.

Yet no deaths or missing persons were recorded. Three people were injured, while government agencies, humanitarian organisations, volunteers, businesses, and communities worked together as conditions changed.

The eruption still caused serious hardship, displacing families and damaging homes and livelihoods, but its human cost could have been far worse. This is disaster risk reduction in practice: not eliminating a hazard, but reducing the likelihood that it becomes a catastrophe.

As the world marks International Day for Disaster Risk Reduction 2026 under the theme Resilience Starts at Home, Indonesia’s experience offers a timely lesson. Resilience is built long before an emergency, through informed communities, capable institutions, inclusive planning, and trusted systems that help people act when every minute matters.

Across Bali, East Java, East Nusa Tenggara, and West Nusa Tenggara, the Australia–Indonesia Partnership for Disaster Risk Management, the SIAP SIAGA Program, supports Indonesian-led efforts to strengthen disaster preparedness, response, and recovery. Working with government agencies, communities, civil society organisations, universities, and businesses, the partnership helps reinforce the systems people rely on when hazards occur.

The response to Mount Semeru did not begin on the day of the eruption.

Following a devastating 2021 event, national and local institutions continued refining preparedness plans, strengthening risk information, conducting simulations, and improving village readiness. When the volcano erupted again in 2025, they were tested under real conditions.

The safer outcome was not the result of a single intervention, it reflected years of Indonesian leadership, operational learning, and cooperation among disaster management agencies, health services, local authorities, humanitarian organisations, volunteers, businesses, and communities.

The same principle is shaping development planning across SIAP SIAGA’s partner provinces. Local governments are increasingly integrating disaster and climate risks into their development plans and strengthening arrangements for preparedness, response, and recovery. Resilience is becoming a development priority, not merely an emergency response function.

These reforms may appear technical. Their purpose is not. They help protect lives, livelihoods, public services, and development gains before hazards occur.

Where Traditional Knowledge Meets Technology

For many Indonesians, the first line of preparedness is their own community.

Indonesia’s Disaster Resilient Village initiative, known by its Indonesian abbreviation DESTANA, helps communities understand hazards, establish evacuation arrangements, strengthen early warning, and incorporate disaster risk into village planning. Women, young people, community leaders, and people with disabilities are increasingly involved, helping ensure that preparedness reflects local realities and diverse needs.

At the foot of Mount Agung, one of Bali’s active volcanoes, the customary village of Temukus offers a vivid example of how traditional knowledge and technology can work together.

During Mount Agung’s 2017 eruption, residents evacuated amid uncertainty and conflicting information. Ni Ketut Sukanti remembers neighbours calling out “Linuh, linuh!”, meaning earthquake in Balinese, and striking metal to warn others before families hurried down narrow roads.

Today, Ni Ketut Sukanti helps organise preparedness through the village’s customary women’s group. Households are listed, residents who may require assistance are identified, livestock are included in evacuation planning, and communities participate in simulations.

Temukus has long read the landscape through generations of observation. Residents watch wind patterns, animal behaviour, and small air vents near rivers that may change when volcanic activity increases. Now, this traditional knowledge is being documented alongside scientific information and translated into practical planning.

Through participatory and drone-based mapping, residents and local authorities identify hazards, evacuation routes, community resources, and culturally important sites. This gives community members a stronger role in identifying risks, assessing how those risks could affect people and livelihoods, and deciding how to prepare.

Their findings contribute to Bali’s Disaster Information System, or Sistem Informasi Kebencanaan. Communities are no longer simply receiving information from authorities. They are helping create evidence that informs public decisions.

Resilience starts with what households and communities already know. Technology can make that knowledge more visible and more useful to institutions able to act.

Closing the Distance Between Warning and Action

The work in Temukus forms part of a wider effort to make disaster information more trusted and actionable.

Across Bali, community knowledge, participatory mapping, and scientific analysis are being brought together to improve decisions before emergencies. The province is also piloting Indonesia’s integrated 112 single emergency number, designed to give residents and visitors one point of contact while strengthening coordination among emergency services.

Technology alone does not create resilience. Its value lies in closing the distance between information and action, ensuring that warnings reach the right people, are understood, and lead to timely decisions.

A Partnership Focused on Stronger Systems

Mount Semeru, Temukus, and Bali’s emergency services are different stories, but they share a common thread. Disaster risk is reduced when households, communities, institutions, and businesses are connected before a crisis.

This is also the foundation of the Australia–Indonesia partnership through SIAP SIAGA. Rather than focusing only on emergency response, the partnership supports Indonesian priorities to strengthen local systems, broaden participation, and develop capabilities that can be sustained over time.

During a recent visit to East Nusa Tenggara, Australia’s Ambassador to Indonesia, Roderick Brazier, reflected on the value of this cooperation. “I am proud to see first-hand the results of the partnership between the Australian Government and the Provincial Government of East Nusa Tenggara. The results are tangible, and we remain committed to strengthening this cooperation so that the systems that have been built continue to grow and deliver benefits to communities.”

The partnership’s value lies not only in individual activities, but in what remains: institutions able to plan and coordinate, communities equipped to act, and relationships ready to support collective action when risks escalate.

Reducing Risk Before it Becomes Loss

Mount Semeru did not become less dangerous in 2025. The system surrounding it was better prepared.

Disaster risk reduction cannot prevent every loss, and safer outcomes cannot be attributed to one program or organisation. They emerge from local leadership, public investment, community readiness, operational learning, and partnerships sustained over time.

SIAP SIAGA is helping reinforce these foundations by supporting locally led systems that connect households, communities, institutions, and development.

As climate and disaster risks intensify across the Indo-Pacific, Indonesia's experience offers a clear lesson: the most effective investment is not rebuilding after disaster, but reducing risk before it strikes. Resilience starts at home, but it succeeds when the systems beyond the front door are ready too.