Understanding Volcanoes and Volcanic Hazards

Between 50 and 70 volcanoes erupt each year—just a fraction of the 1,000 identified volcanoes that may erupt in the near future. When compared with the catastrophic loss of lives and property resulting from typhoons, earthquakes, and floods, losses from the more infrequent but equally devastating volcanic eruptions are often overlooked. Volcanic events are usually dramatic, but their various effects may occur almost imperceptibly or with horrendous speed and destruction. The intermittent nature of this activity makes it difficult to maintain public awareness of the risks. Assessing volcanic hazards and their risks remains a major challenge for volcanologists. Several generations ago, only a small, international fraternity of volcanologists was involved in the complex and sometimes dangerous business of studying volcanoes. To understand eruptions required extensive fieldwork and analysis of the eruption products—a painstaking process. Consequently, most of the world’s volcanoes had not been studied, and many were not yet even recognized. Volcano research was meagerly supported by some universities and a handful of government-sponsored geological surveys. Despite the threats posed by volcanoes, few volcanological observatories had been established to monitor their activity. Volcanology is now a global venture. Gone are the days when volcanologists were educated or employed chiefly by the industrial nations. Today, volcanologists and geological surveys are located in many nations with active volcanoes. Volcanological meetings, once limited to geologists, geophysicists, and a smattering of meteorologists and disaster planners, have greatly expanded. Initially, it was a hard sell to convince volcanologists that professionals from the “soft sciences” could contribute to the broad discipline of volcanology. However, it has become clear that involving decision makers such as urban planners, politicians, and public health professionals with volcanologists is a must when exploring and developing practical, effective volcanic-risk mitigation. Beginning in 1995, the “Cities on Volcanoes” meetings were organized to introduce an integrated approach that would eventually help mitigate the risks of volcanic eruptions. The first conference, held in Rome and Naples, Italy, encompassed a broad spectrum of topics from the fields of volcanology, geographic information systems, public health, remote sensing, risk analysis, civil engineering, sociology and psychology, civil defense, city management, city planning, education, the media, the insurance industry, and infrastructure management. The stated mission of that meeting was to “better evaluate volcanic crisis preparedness and emergency management in cities and densely populated areas.” Since that meeting nearly twenty years ago, Cities on Volcanoes meetings have taken place in New Zealand, Hawaii, Ecuador, Japan, Spain, and Mexico; the 2014 venue was Yogyakarta, Indonesia. The significant and rewarding result of these efforts is a growing connection between basic science and the practical applications needed to better understand the myriad risks as well as the possible hazard mitigation strategies associated with volcanic eruptions. While we pursue this integrated approach, we see advances in the technologies needed to evaluate and monitor volcanoes. It is impossible to visit all the world’s restless volcanoes, let alone establish effective monitoring stations for most of them. However, we can now scrutinize their thermal signatures and local ground deformation with instruments on earth-observing satellites. When precursory activity is detected by remote sensors in an area where a population is at risk, teams can be deployed for ground-based monitoring of that activity. In addition, by evaluating a volcano’s past eruption history, scientists can forecast both future activity and the possible risks to inhabitants. Using physics-based modeling, there is a better understanding of the types and severity of potential eruption phenomena such as pyroclastic flows, ash eruptions, gaseous discharge, and lava flows. Field observations of changes indicating an imminent eruption are now monitored with geophysical and geochemical instrumentation that is smaller, tougher, and more affordable. Volcanology has evolved into a broader, integrated scientific discipline, but there is much still to be accomplished. The new generation of volcanologists, who have the advantage of knowing the theoretical underpinnings of volcanic activity, can now turn to the allied endeavor of reducing risk—their aspiration for the 21st century.