Unfortunately, people near the volcano were not alerted. They remained in their homes and perished. Hazard assessment is essentially a technical professional activity, but it is only the precursor to hazard management, which involves the messy political process of balancing interests and priorities, and of implementing change. As an example of long-term measures, factories sometimes can be sited way from seismic zones or hurricane belts. If that is not possible, they can be designed for more hazard resistance.
Cities can adopt codes to prevent construction in areas most susceptible to landslides.
Many affordable ways to improve buildings are available to people in developing countries. In Guatemala, for instance, adobe homes built with wooden frames provide more reinforcement during earthquakes. We should build our schools, hospitals, bridges, and power plants away from hazard areas, or to withstand known dangers. We must protect our natural resources and precious cultural treasures. Fire codes, dam safety standards, seismic codes, and other approaches all can help, as can insurance policies that provide disincentives for building in the most vulnerable seismic zones, fire-prone areas, flood plains, and low coastal areas.