The deposits of the pyroclastic density currents from the August 2006 eruption of Tungurahua show three facies associations depending on the topographic setting: the massive, proximal cross-stratified, and distal cross-stratified facies. (1) The massive facies is confined to valleys on the slopes of the volcano. It contains clasts of >1 m diameter to fine ash material, is massive, and interpret...

The Indian Peak volcanic field is representative of the more than 50,000 km3 of ashflow tuff and tens of calderas in the Great Basin that formed during the Oligocene-early Miocene "ignimbrite flareup" in southwestern North America. The field formed about 32 to 27 Ma in the southeastern Great Basin and consists of the centrally positioned I n d i Peak caldera complex and a surrounding blanket of...

In this paper we present a model for the growth of a maar-diatreme complex in a shallow marine environment. The Miocene-age Costa Giardini diatreme near Sortino, in the region of the Iblei Mountains of southern Sicily, has an outer tuff ring formed by the accumulation of debris flows and surge deposits during hydromagmatic eruptions. Vesicular lava clasts, accretionary lapilli and bombs in the ...

The youngest (last 1500 years) volcanic eruptions of Lipari, within the Aeolian Archipelago, produced prominent pumice cone Monte Pilato and obsidian lava flows Rocche Rosse Forgia Vecchia, concentrated in north-eastern sector island as well highly dispersed white-coloured, fine-grained tephra layers rhyolitic composition terrestrial marine settings on regional scale. Here we describe detail st...

For active volcanoes, knowledge about probabilities of eruption and impacted areas becomes valuable information for decision-makers to develop short- long-term emergency plans, which probabilistic volcanic hazard assessment (PVHA) is needed. High-resolution or spatially extended PVHA requires extreme-scale high-performance computing systems. Within the framework ChEESE (Center Excellence Exasca...

sorkheh-dizaj apatite-iron oxide deposit is located 32 km southeast of zanjan. the area is situated within the tarom subzone of western alborz-azarbaijan structural zone. the oldest units at the sorkheh-dizaj area are eocene trachyte, trachyandesite, olivine basalt and volcanoclastic brecciate tuff and lapilli tuff which intruded by a quartz-monzonite, monzonite and granite subvolcanic pluton o...

Basaltic eruptions are commonly associated with lava emissions and relatively weak explosive activities, but they can sometimes produce strong eruptive phases. In April November 2005, two paroxysmal events occurred within the summit crater of Karthala basaltic shield volcano (Grande Comore Island, Comoros), which hosted a water lake before each these events. Both 2005 ash plumes spread across C...

The Azores archipelago is a small and remote region with low population levels where the issues of sustainability and autonomy have a lways been important and present s ignif icant economic consequences. Currently, the construction industry uses many imported products; however, masonry products are almost exclusively provided by local industries. For its production, masonry uses a natural volca...

The sedimentological, lithological and textural characteristics of the Brown Tuffs (BT) pyroclastic deposits, combined with their grain-size, componentry geochemical glass compositions, are here investigated to obtain information on transport depositional mechanisms corresponding density currents (PDCs). BT widespread reddish-brown grey, ash-rich deposits generated by pulsating hydromagmatic ex...

The investigation of heterogeneous magma systems enhances the understanding differentiation and transfer processes in active volcanoes, thus constraining dynamics driving eruptions related hazard. Magma heterogeneity is generally preserved coeval juvenile products explosive eruptions, as it occurs Upper Pumice sequence, emplaced by last sub-Plinian eruption at Nisyros volcano (Greece). deposit ...