b'Carnegie Science|Fall 2019 5How to Forecast On the Cusp Volcanic EruptionsSome volcanoes take their time, experiencing years-long unrest, before eventually erupting.This makes it difficult to forecast when they pose a danger, but Carnegies Diana Roman and Pennsylvania State Universitys Peter LaFemina are trying to change that. Dormancy, brief unrest, eruptionthis is a familiar pattern for many volcanoes, and for many parents, joked Roman. But for some volcanoes the unrest is anything but brief, potentially lasting for decades. It turns out that these so-called persistently restless volcanoes experience three different states of unrest, some of which are more likely to result in explosive eruptions than others, according to Roman and LaFeminas 10-year research project on the Telica Volcano in Nicaragua. Geochemistry, Geophysics, Geosystems published their latest results.Persistently restless volcanoes remain right on the cusp of Diana Roman is at Telica Volcano in Nicaragua with an assistant (above) and working being about to erupt, periodically tipping into outright eruption,with instrumentation (below). explained lead author Roman.Images courtesy Carnegie Institution for Science (above) and Matthew Scott (below)She, LaFemina, and an international group of collaborators found that Telica experienced three states of unrest during theThe second state is characterized by a series of weak decade, two of which may lead to eruptions.explosions until one comes along that is strong enough to The first is accompanied by relatively steady release of gasremove the obstruction. However, if the explosions only partially as well as changes in seismic activity. In this state, gas canremove the blockage, it can lead to the third, destabilized state, move easily through and out of the system of cracks andin which pressure rapidly accumulates, driving deformation of reservoirs underlying the volcano, avoiding accumulatingthe surrounding landscape and large explosions that include pressures that lead to explosions. But sometimes one of theseejection of rock fragments. Roman and LaFemina believe that channels gets sealed off, blocking the release of gas. The secondthe 2011 eruption of Telica is an example of the former and the and third states are defined by the strength of the blockage. 2015 eruption is an example of the latter. Over the course of our decade of monitoring Telica, we observed all three of our proposed states of unrest, LaFemina noted. This reinforces the importance of continuous surveillance efforts. He and Roman said that their teams findings could lead to a forecasting model for persistently restless volcanoes, but first it is critical to establish similar patterns at other volcanoes like Telica.SUPPORT:The National Science Foundation (NSF), NASA, the European Commission FP6 Programme, the DECADE/Deep Carbon Observatory, and Instituto Nicaragense de Estudios Territoriales (INETER) supported this work.Data was obtained though the Committee on Earth Observation Satellites (CEOS) Volcano pilot project and working group and the German Aerospace Center. This material is based on services provided by the UNAVCO Facility with support from NSF and NASA. This work was also conducted as part of the Optimizing satellite resources for the global assessment and mitigation of volcanic hazards Working Group supported by the John Wesley Powell Center for Analysis and Synthesis, funded by the U.S. Geological Survey.'