Piton de la Fournaise and Karthala are both shield volcanoes in the southwest Indian Ocean. This publication summarizes the work done on these very active basaltic volcanoes. Piton de la Fournaise has a long history of scientific research and monitoring, with many data collected during recent eruptions. It is certainly one of the most studied volcanoes in the world. The work presented in this monograph includes geological, geophysical, geochemical and petrological aspects, but also studies on physical geography, natural hazards and the sociological and behavioural approaches.' The Karthala volcano may be less well known, but it serves as an interesting comparison to Piton de la Fournaise. Although situated close to the volcanoes of Hawaii, it differs from them by its more alkaline magmas and less frequent activity. It was also monitored for more than 25 years, producing extraordinary eruptions in recent years.

Hawaiian Volcanoes, From Source to Surface is the outcome of an AGU Chapman Conference held on the Island of Hawai‘i in August 2012. As such, this monograph contains a diversity of research results that highlight the current understanding of how Hawaiian volcanoes work and point out fundamental questions requiring additional exploration. Volume highlights include: Studies that span a range of depths within Earth, from the deep mantle to the atmosphere Methods that cross the disciplines of geochemistry, geology, and geophysics to address issues of fundamental importance to Hawai‘i’s volcanoes Data for use in comparisons with other volcanoes, which can benefit from, and contribute to, a better understanding of Hawai‘i Discussions of the current issues that need to be addressed for a better understanding of Hawaiian volcanism Hawaiian Volcanoes, From Source to Surface will be a valuable resource not only for researchers studying basaltic volcanism and scientists generally interested in volcanoes, but also students beginning their careers in geosciences. This volume will also be of great interest to igneous petrologists, geochemists, and geophysicists.

The impact of natural disasters has become an important and ever-growing preoccupation for modern societies. Volcanic eruptions are particularly feared due to their devastating local, regional or global effects. Relevant scientific expertise that aims to evaluate the hazards of volcanic activity and monitor and predict eruptions has progressively developed since the start of the 20th century. The further development of fundamental knowledge and technological advances over this period have allowed scientific capabilities in this field to evolve. Hazards and Monitoring of Volcanic Activity groups a number of available techniques and approaches to render them easily accessible to teachers, researchers and students. This volume is dedicated to geological and historical approaches. The assessment of hazards and monitoring strategies is based primarily on knowledge of a volcano’s past behavior or that of similar volcanoes. The book presents the different types of volcanic hazards and various approaches to their mapping before providing a history of monitoring techniques.

Ocean island volcanoes constitute some of the most prominent and rapidly-formed features on Earth, and yet they cannot be explained by conventional plate tectonics. Although typically associated with intraplate settings (hotspots), these volcanoes also occur in different geodynamic settings (near mid-ocean ridges). The nature of ocean island magmatism is still the subject of intense debate within the geological community. Traditionally it has been linked to the presence of mantle plumes at depth (e.g. Hawaii), although the interaction with plate tectonics is also recognized to play a significant role (e.g. Azores, Galápagos). Magma compositions may range from basaltic to more differentiated, which consequently is accompanied by striking changes in the eruption style from effusive-dominated to highly explosive volcanism. Understanding how these magmas evolve and how volcanic processes act at ocean island volcanoes are key issues of modern volcanology. Moreover, the growth of ocean island volcanoes from their rise on the seafloor as seamounts, to island emergence and subsequent formation of shield volcanoes (and in some cases large caldera volcanoes) is governed by multiple interrelated changes. It is well known that competing processes model ocean island volcanoes during alternating and/or coeval periods of construction and destruction. The geological evolution of these volcanoes results from the balance among volcanism, intrusions, tectonics, subsidence/uplift, mass wasting, sedimentation, and subaerial and wave erosion. A better knowledge of the interplay between these processes is crucial to obtain a more comprehensive understanding of the evolution of such volcanoes, and to the eventual formulation of a unified model for ocean island evolution. Ocean islands are especially vulnerable to volcanic eruptions and other geological hazards on account of their typical small size, rough topography and isolation, which make risk management and evacuation difficult. Volcanic eruptions, in particular, may have a significant impact on local populations, infrastructures, economy and even on the global climate. It is therefore fundamental to monitor these volcanoes with complementary geophysical, geodetic and geochemical techniques in order to forecast future eruptions and their impacts. However, the assessment of volcanic hazards on ocean islands is challenging due to the large variety of phenomena involved (e.g. lava flows, tephra fallout, pyroclastic density currents, lahars, gas emissions). Different approaches are used to assess volcanic hazards, either based on empirical methods or sophisticated numerical models, focusing on a single phenomenon or the combination of different hazards. This Frontiers Research Topic aims to promote discussion within the scientific community, representing an important step forward in our knowledge of ocean island volcanoes in order to serve as a reference for future research.