Between 1971 and, the Southeast Crater was the most productive of the four summit craters of Mount Etna, with activity that can be compared, on a global scale, to the opening phases of the Pu'u 'Ō'ō-Kūpaianaha eruption of Kīlauea volcano, Hawai'i. The period of highest eruptive rate was between 1996 and 2001, when near-continuous activity occurred in five phases. These were characterized by a wide range of eruptive styles and intensities from quiet, non-explosive lava emission to brief, violent lava-fountaining episodes. Much of the cone growth occurred during these fountaining episodes, totaling 105 events. Many showed complex dynamics such as different eruptive styles at multiple vents, and resulted in the growth of minor edifices on the flanks of the Southeast Crater cone. Small pyroclastic flows were produced during some of the eruptive episodes, when oblique tephra jets showered the steep flanks of the cone with hot bombs and scoriae. Fluctuations in the eruptive style and eruption rates were controlled by a complex interplay between changes in the conduit geometry (including the growth of a shallow magma reservoir under the Southeast Crater), magma supply rates, and flank instability. During this period, volume calculations were made with the aid of GIS and image analysis of video footage obtained by a monitoring telecamera. Between 1996 and 2001, the bulk volume of the cone increased by~36×10 6 m 3 , giving a total (1971-2001) volume of~72×10 6 m 3 . At the same time, the cone gained~105 m in height, reaching an elevation of about 3,300 m. The total DRE volume of the 1996-2001 products was~90×10 6 m 3 . This mostly comprised lava flows (72×10 6 m 3 ) erupted at the summit and onto the flanks of the cone. These values indicate that the productivity of the Southeast Crater increased fourfold during 1996-2001 with respect to the previous 25 years, coinciding with a general increase in the eruptive output rates and eruption intensity at Etna. This phase of intense summit activity has been followed, since the summer of 2001, by a period of increased structural instability of the volcano, marked by a series of important flank eruptions.

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[1] Pure CO 2 fluid inclusions are observed in quartz xenoliths from four lava flows in the Island of Vulcano, corresponding to distinct activity stages during the last 120 kyr. Xenoliths, which consist of aggregates of quartz grains, are present in lavas of contrasting composition ranging from basaltic-andesites to rhyolites. Two main generations of CO 2 inclusions are observed: early (type I) inclusions were trapped prior to the ascent of the host xenoliths, while type II inclusions were trapped during the ascent into the host magma. Fluid inclusions show a bimodal distribution of homogenisation temperatures, corresponding to two distinct density intervals: 0.89-0.52 g/cm 3 (type I) and 0.42-0.13 g/cm 3 (type II). Type I inclusions indicate pressures of 0.56-0.33 GPa (21-13 km), relating to the levels of xenolith entrapment in the host lavas. Type II fluid inclusions show considerably lower pressures ranging from 0.14 to 0.03 GPa (5.5-3 km). Present data suggest ponding of mantle-derived magmas in at least two distinct reservoirs, located at lower crustal depths and at shallow levels, respectively. Combined fluid inclusion and petrological data suggest that the deep reservoirs were the sites of extensive fractional crystallization, mixing with source-derived magmas, and various degrees of crustal assimilation. Evolutionary processes also occurred inside shallow magma chambers, in which deep magma mixed with residing melts and rested for short periods of time before being erupted to the surface.

[1] In the islands of Faial and Pico (the Azores), fluid inclusions are hosted in megacrysts of olivine (Mg#80-88) and clinopyroxene (Mg#79-90) in highly porphyritic lavas and in mineral assemblages of ultramafic xenoliths. Rare inclusions are contained in olivine phenocrysts (Mg# < 80) and plagioclases in poorly porphyritic lavas. Trails of late-stage inclusions are predominant over isolated early-stage inclusions. Almost all inclusions are re-equilibrated and the trapped fluid consists of pure CO 2 (Tm from À56.5 to À57.2). Rare early-stage inclusions may contain dypingite or Mg-calcite, which indicates that in earlier times some water was present along with CO 2 . Barometric data indicate that CO 2 inclusions in xenoliths from the two islands equilibrated at maximum pressures of 570-586 MPa (19.7-21.2 km), while in poorly porphyritic lavas from all the fissure zones at 465-508 MPa (16.4-18.1 km). Maximum pressure values of 463 MPa (16.8 km) and 492 MPa (17 km) were recorded for the central volcanoes of Pico and Faial, respectively. Further trapping/re-equilibration was recorded at 156 MPa in Faial (5.6 km), in plagioclase phenocrysts in mugearites. All these pressures correspond to magma ponding sites and to its crystallization and can be useful for tracing the progressive thickening of a dense transition zone, below the geophysical Moho. The ability to extract rapidly the stored magmas from these volcanic systems strictly depends on the different tectonic styles, acting in this transition zone. Magmatic evolution in small and short-lived intracrustal reservoirs, not necessarily coaxial with main conduit system, was enhanced at the intersection of differently oriented lineaments.

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Oceanic islandssuch as the Azores in the mid-North Atlanticare periodically exposed to large storms that often remobilize and transport marine sediments along coastlines, and into deeper environments. Such disruptive events create depositsdenominated tempestiteswhose characteristics by storm events is the main process of sediment deposition acting on steep and narrow shelves subjected to high-energetic environments, such as the insular shelves of open-sea volcanic islands.

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51Massive fossil shell accumulations require particular conditions to be formed and may 52 provide valuable insights into the sedimentary environments favouring such 53 concentrations. Shallow-water shell beds appear to be particularly rare on reefless 54 volcanic oceanic islands on account of narrow, steep and highly-energetic insular 55 shelves where the potential for preservation is limited. The occurrence of an exceptional 56 coquina (Pedra-que-pica) within the Miocene-Pliocene deposits of Santa Maria Island 57 (Azores), therefore provides a rare opportunity to understand the conditions that led to 58 the formation and preservation of a massive shell bed at mid-ocean insular setting. This 59 study provides a detailed analysis regarding a 10-11 m-thick bivalve-dominated fossil 60 assemblage exposed at Pedra-que-pica on Santa Maria Island in the Azores. Integration 61 of taphonomical, palaeoecological and sedimentological observations are used to 62 reconstruct the genesis of the coquina bed and related events, and to discuss why such 63 exceptional sedimentary bodies are so rare on shelves around reefless volcanic oceanic 64 islands. 65 The sequence at Pedra-que-pica demonstrates a complex succession of sedimentary 66 environments in response to the drowning of an existing coastline during a period of 67 rapid sea-level rise. The Pedra-que-pica shell bed incorporates storm-related materials 68 and possible debris falls that originated nearby in a shallow and highly productive 69 carbonate factory. Deposition took place below fair-weather wave base, at around 50 m 70 depth, as inferred from the overlying volcanic succession. The preservation of this 71 coquina was favoured by deposition on a platform laterally protected by a rocky spur, 72 combined with rapid burial by water-settled volcanic tuffs and subsequent volcanic 73 effusive sequences. The recent exhumation of the deposit is the result of island uplift 74 and subsequent erosion.75 4 76 77