The volcano represents perhaps the quintessential example of mankind versus nature, and the classic caricature of the relationship of people to god(s). We still can’t stop them from erupting, but science has certainly given us a lot of predictive power and a lot of tools to ameliorate their effects. Aside from providing many valuable signals to a coming eruption, our modern understanding of volcanoes has given us the ability to identify particular sources of danger that would be overlooked otherwise. For example, some volcanoes have a history of lahars, mudflows that can sweep down quickly and destroy human lives. This history is often buried in the landscape, and/or requires scientific knowledge to properly interpret.
Many volcanoes exhibit clear signs before a major eruption – rumblings in the earth, reflecting rising magma, deformation of the land itself in and/or near the volcano, reflecting pressure from beneath, gas emissions, as magma approaches the surface, and thermal changes in waters associated with the volcano, reflecting increasing heat near the surface. Every volcano is unique, but there are commonalities. Of course, many of these signs should be obvious even to unsophisticated observers. Yet time and again, people living close to volcanoes, like Vesuvius in Italy, have failed to take heed of warnings. Vesuvius in particular goes through long periods of quiescence, often lasting centuries, but inevitably blows its top eventually. At the end of the 13th century it entered a period of unusual quiet that lasted more than 200 years. People clustered around the volcano again, cattle even grazed in its crater, and vineyards and orchards adorned its slopes. But in 1631 it erupted again, killing thousands. There was plenty of rumbling, for months, prior to the eruption, as well as other precursors. But so much time had passed that people forgot. When Vesuvius erupted in the 20th century, the results were far less lethal.
One could argue that it wasn’t so much volcano prediction that improved, but other things – communication, transportation, infrastructure generally, support systems. In Japan, where many live in close proximity to active volcanoes, there are many systems to give warning and ameliorate effects. Lahars are directed through channels instead of driving across neighborhoods, and their passage automatically trips sensors that trigger warnings downslope. More dramatic is scientific success with tsunamis, which historically (and prehistorically) devastated communities with almost no warning. Because tsunamis often originate hundreds or thousands of miles from the places they devastate, there is often time to give warning. The Pacific Basin tsunami warning system is highly developed. A submarine earthquake near Peru will quickly yield warnings in Hawaii and Japan. Of course one might argue that since a large tsunami is always preceded by a striking drop in the ocean level near shore, tsunamis have a built-in warning system. But we have seen time and again that people do not interpret this properly. This illustrates the folly of depending of folk knowledge or common sense to protect people from harm. Only systematic methods founded on solid science produce dramatic results.