This, the Hiroshi Wakita Volume III is a special publication brought out by Springer to honor Professor Wakita for his contributions to science. These have been closely linked with one of the major objectives of this 2008 International Year for the Earth Planet. Reducing natural risks in active tectonic and volcanic environments by searching for and detecting early warning signatures related to earthquakes and volcanic eruptions has been a major research goal for Hiroshi Wakita.

Terrestrial fluids, earthquakes and volcanoes: The Hiroshi Wakita Volume II is a special publication to honor Professor Hiroshi Wakita for his scientific contribution to science and commemorate his 10th anniversary as Emeritus Professor at The University of Tokyo. This second special issue of Pure and Applied Geophysics consists of 10 original contributions written by researchers from Japan, Germany, Italy, Costa Rica, Sweden, El Salvador, Turkey, USA, Greece, and Spain. The discussed subjects include research on earthquake-related hydrologic and geochemical observed temporal changes, diffuse degassing in active tectonic and volcanic settings, the observed changes on gas emission and temperature prior volcanic eruptions, magma degassing signature in the groundwater system of active volcanic, and the development of recent technology for continous monitoring of volcanic gases. The Hiroshi Wakita volume II will be useful to students and professional researchers who are interested in the role of terrestrial fluids in earthquakes and volcanic activity.

The Hiroshi Wakita Volume I is a collection of original papers regarding the role of terrestrial fluids in earthquake and volcanic processes. The importance of monitoring volcanic gases for studying volcanic eruptions is widely recognized by the scientific community. On the other hand, the usefulness of hydrologic and geochemical monitoring in earthquake studies, especially in earthquake prediction, has been controversial. This Pure and Applied Geophysics volume provides the results of some of the most recent studies on terrestrial fluids involved in both processes.

The volume honors Hiroshi Wakita for his scientific contributions. Volume II will be published later in 2006. Both volumes should be useful to researchers and graduate students in the field.

La Reunion is an oceanic intra-plate volcanic island located at the southern-most part 0 of the Mascarene Basin at 21 0 07' S, 55 32' E (Figure 1). It lies south of the Mascarene Plateau and Mauritius Island but is a distinct topographic feature on the rather flat ocean bottom of the Mascarene Basin, whose age is paleocene in the vicinity of the island (Schlich, 1982), and whose lowest point is more than 4000m deep. La Reunion is ellip tical in shape (50 X 70 km) with a NW-SE elongation. It is composed of two volcanoes: Piton des Neiges and Piton de la Fournaise. A third volcanic structure has been recent ly discovered on the east submarine flank of the island (Unat et aI., submitted). Piton des Neiges, a dormant and deeply eroded volcano, rises to a height of 3069 m and oc cupies the northwestern two-thirds of the island. Piton de la Fournaise (2630 m), one of the most active basaltic volcanoes in the world, began to grow more than 3. 5 X 1O years ago on the southeast flank of Piton des Neiges. The evolution of Piton de la Fournaise (Chevallier and Bachclery, 1981) is marked by the formation of three sub-concentric nested calderas (Figure 2). The boundaries of the two older calderas are more or less buried or eroded."