Volcanology, Risk assesment for natural disasters

Mount Etna in Sicily (Italy) shows N 2500 years of interactions between volcanic eruptions and human activity, and these are well documented in historical sources. During the last 400 years, flank eruptions have had major impacts on the urban fabric of the Etna region, especially in 1651–54, 1669, 1923 and 1928, and it is the last of these which is the focus of this paper. A detailed field and historical reconstruction of the 1928 eruption is presented which allows three themes to be discussed: the evolution of the flow field, lava volume and average magma discharge rate trend; the eruption's human impact, particularly the destruction of the town of Mascali; and the recovery of the region with reconstruction of Mascali in a new location. Detailed mapping of lava flows allowed the following dimensions to be calculated: total area, 4.38 × 10 6 m 2 ; maximum length, 9.4 km; volume , 52.91 ± 5.21 × 10 6 m 3 and an average effusion rate of 38.5 m 3 s −1. Time-averaged discharged rates are calculated allowing the reconstruction of their temporal variations during the course of the eruption evidencing a high maximum effusion rate of 374 m 3 s −1. These trends, in particular with regard to the Lower Fissure main phase of the eruption, are in accordance with the 'idealized discharge model' of Wadge (1981), proposed for ba-saltic eruptions driven by de-pressurization of magma sources, mainly through reservoir relaxation (i.e. elastic contraction of a magma body). The eruption took place when Italy was governed by Mussolini and the fascist party. The State response both, during and in the immediate aftermath of the eruption and in the years that followed during which Mascali was reconstructed, was impressive. This masked a less benign legacy, however, that can be traced for several subsequent decades of using responses to natural catastrophes to manufacture State prestige by reacting to, rather than planning for, disasters.

Previous published data, combined with our results of 13 new radiocarbon ages and
extensive geological fieldwork, indicate that during the past 11 ka 24 monogenetic basaltic eruptions
occurred in the north sector of Gran Canaria. These eruptions can be grouped into three periods of
eruptive activity: 1900–3200 14C a BP; 5700–6000 14C a BP; and an older period represented by only
one eruption, El Draguillo, dated at 10 610
190 14C a BP. Archaeological studies have shown that the
more recent eruptions affected prehistoric human settlements on the island. Field studies demonstrate
that the eruptions typically built strombolian cones (30–250min height) and associated relatively long
lava flows (100–10 350m in length); a few eruptions also produced tephra fall deposits. The total
erupted volume of these eruptions is about 0.388km3 (46.1% as tephra fall, 41.8% as cinder cone
deposits and 12.1% as lava flows). The relatively low eruption rate (0.04 km3 ka1) during the past
11 ka is consistent with Gran Canaria’s stage of evolution in the regional volcano-tectonic setting of the
Canary Archipelago. The results of our study were used to construct a volcanic hazards map that
clearly delimits two sectors in the NE sector of Gran Canaria, where potential future eruptions would
pose a substantial risk for densely populated areas

In this article, we show why the geological model of the 21 August 2017 earthquake proposed by Nappi et al. (2018) has less uncertainty than the source model proposed by De Novellis et al. (2018). As a matter of fact, the Nappi et al. (2018) model takes into account all geophysical and geological information collected soon after the earthquake. On the contrary, the model proposed by De Novellis et al. (2018) is based on a limited database, which does not include (1) the available geological and macroseismic information and (2) the extensive scientific literature concerning the correlation between seismic source and surface faulting, also in volcanic areas similar to Ischia. Nevertheless, we are grateful for the comments from De Novel-lis et al. (2018) because they give us the opportunity to consider the epistemological landscape in which we should frame the research for the best source model of the 21 August 2017 Casamicciola earthquake.

Accurate and precise morphometric modelling
can be extended to past eruptions after a careful palaeogeomorphological
reconstruction of volcanic landforms in
an oceanic island. This reconstruction was used to derive
the pre-, post-eruption and present-day digital elevation
models (DEM). The correct pixel size, interpolation
method and quality of these DEMs are discussed. The
process in a Geographical Information System framework
of the geological information of cone, lava flow and tephra
fall deposits together and the aforementioned DEMs
allowed the determination of main morphological features
of these volcanic landforms and their derivatives. The
calibration and validation of morphometric modelling were
performed on simulated volcanic landforms, and verified
by a case study: a typical Holocene monogenetic basaltic
eruption at Gran Canaria Island (Spain).

Por más de dos años el volcán Chillán perteneciente al Complejo Volcánico Nevados de Chillán (CVNC), ha mantenido en alerta a la población cordillerana de la Región de Ñuble. Recientemente el Servicio Nacional de Geología y Minería ha decidido cambiar la alerta amarilla por alerta naranja ya que se ha detectado una alta actividad eruptiva y a raíz de esto se han desarrollado una serie de investigaciones al respecto para prevenir un desastre mayor que perjudique a las localidades aledañas. Este documento se centra en responder aquellas preguntas que surgen desde el área de la Glaciología, ¿Qué sucede cuando un volcán entra en erupción debajo o muy cerca de un glaciar?.

The Pomici di Mercato (PdM, 8,010±40 a), also
known in the literature as Pomici Gemelle or Pomici di
Ottaviano, is one of the oldest Plinian eruptions of Somma-
Vesuvius. This eruption occurred after the longest (7 ka)
quiescence period of the volcano and was followed by more
than 4 ka of repose. The erupted magma is phonolitic in
composition. All the products have very low phenocrysts
content (less than 3%) and show evidence of mineralogical
disequilibria. They contain K-feldspar ± clinopyroxene
(salite and diopside) ± plagioclase ± garnet ± biotite ±
amphibole ± apatite ± Fe-Ti oxides. Pumice fragments
collected at different stratigraphic heights are slightly less
evolved and more enriched in radiogenic Sr composition
upsection. The glass composition is fairly homogeneous in
single pumice fragment and among pumice fragments from
different layers. Glass separated from pumice fragments
collected at different stratigraphic heights is homogeneous
in the Sr-isotope composition (around a value of 0.70717).
Glass is in isotopic equilibrium with salite throughout the
entire sequence and with diopside at the base of the
sequence. Diopside becomes more radiogenic upsection,
reaching a value of 0.707458±7, whereas feldspar is
consistently slightly less radiogenic than glass. Nd-isotope
composition is fairly uniform (ca. 0.51247) through the
whole sequence. The isotopic disequilibria among glass,
feldspar and diopside, together with the homogeneous
isotopic composition of pumice glass in equilibrium with
salite, and the mineralogical disequilibria between plagioclase
and K-feldspar, imply that most of the diopside
and plagioclase crystals are xenocrysts incorporated into
the phonolitic magma during residence in a magma
chamber and/or during ascent towards the surface. The
PdM Tephra are compositionally and isotopically similar to
the phonolitic, first-erupted products of the subsequent
Pomici di Avellino Plinian eruption. On the basis of this
similarity, we suggest that the magma feeding both
eruptions resulted from the tapping of a unique magma
chamber. Prior to the PdM eruption, this chamber was
formed by a large and homogeneous phonolitic magma
body. After the PdM eruption, as a consequence of new
arrivals of more radiogenic in Sr, less-differentiated magma
batches, the magma chamber progressively developed a
slightly stratified phonolitic uppermost portion, capping a
tephriphonolitic layer, both emitted during the subsequent
Pomici di Avellino eruption.

Indonesia’s Mount Merapi is one of the world’s most
active, dangerous volcanoes. Its 2010 eruption – the
largest following the 20 th century – and succeeding
2011 lahar events killed 389 persons and injured and
displaced many more. One way to mitigate a disas-
ter’s impact is the provision of reliable information
to the public through a well-established early warning
system (EWS). A well-managed information flow net-
work is the key to delivering early warning informa-
tion, however, there is a lack of understanding on the
information transfer down to the citizens. In addition,
implementing the 2007 disaster management law may
have affected Merapi’s EWS. This study reinvestigates
Merapi’s EWS information flow through the construc-
tion of an information flow network. A single infor-
mation flow network was difficult to construct due to
the inconsistency of structures per district. Different
networks had to be constructed for volcanic eruptions
and lahars in each district. Inconsistencies were also
found in the roles of the agencies that determine when
evacuation orders would be issued. The system also
had data transfer gaps and vulnerabilities such as re-
dundancies, mistransfers and bottlenecks. Its use of
forecasting information as a basis for decision-making
must be reviewed for lahar information flow networks.
Improving Merapi’s EWS must involve handling these
issues.

Since natural disasters occur, facilities which are related to this vital element are underground so, it is difficult to rapid access to correct, accurate and reliable information of urban water distribution network. Therefore, this article has done operationally in Boukan city which is located in Western Azarbaijan of Iran and it tries to represent by using rules and data of construction management, urban designing and capabilities of Geographical Information system (GIS) in urban water management at the time of natural disasters. Structure of this article is like that in first we established a comprehensive data base related to water utilities by collecting, entering, saving and data management, then by modeling water utilities we had practically considered its operational aspects related to water utilities problems in urban regions.

The origin and life cycle of ocean islands have been debated since the early days of Geology. In the case of the Canary archipelago, its proximity to the Atlas orogen led to initial fracture-controlled models for island genesis, while later workers cited a Miocene-Quaternary east-west age-progression to support an underlying mantle-plume. The recent discovery of submarine Cretaceous volcanic rocks near the westernmost island of El Hierro now questions this systematic age-progression within the archipelago. If a mantle-plume is indeed responsible for the Canaries, the onshore volcanic age-progression should be complemented by progressively younger pre-island sedimentary strata towards the west, however, direct age constraints for the westernmost pre-island sediments are lacking. Here we report on new age data obtained from calcareous nannofossils in sedimentary xenoliths erupted during the 2011 El Hierro events, which date the sub-island sedimentary rocks to between late Cretaceous and Pliocene in age. This age-range includes substantially younger pre-volcanic sedimentary rocks than the Jurassic to
Kirsten Zaczek, Valentin R. Troll, Mario Cachao, Jorge Ferreira, Frances M. Deegan, Juan Carlos Carracedo, Vicente Soler, Fiona C. Meade & Steffi Burchardt

Miocene strata known from the older eastern islands and now reinstate the mantle-plume hypothesis as the most plausible explanation for Canary volcanism. The recently discovered Cretaceous submarine volcanic rocks in the region are, in turn, part of an older, fracture-related tectonic episode.

Presentazione su "OrticaLab" dell'incontro tenuto da Giovanni Gugg sul tema "Vite magmatiche. Immagine e immaginario di un vulcano in città", presso il Godot di Avellino, per il ciclo di conferenze curato da Marina Brancato. Appuntamento del 26 maggio 2015.

Vulcano island is a composite volcanic edifice located in the south-central sector of the Aeolian Archipelago
(Tyrrhenian Sea, Italy). It is the southernmost tip of the southern branch of the Y-shaped archipelago; in particular,
it is part of the bigger Lipari-Vulcano volcanic complex that comprises the two southernmost islands of the
archipelago. This branch of the archipelago is NNW-SSE oriented and represent the off-shore prolongation of
the Tindari-Letojanni tectonic lineament in the NE Sicily, splitting the Appennine chain on the west, from the
Calabrian arc on the East. N-S compression seems to affect the western side of this NNW-SSE lineament, while
extension affects the eastern one, with active volcanism and a NW dipping Benioff plane. Historic activity at Vulcano
has been characterized by frequent transitions from phereatomagmatic to minor magmatic activity. The last
eruption in 1888-90 was characterized by energetic explosive pulses and defines the so-called “vulcanian” type of
activity. Since then, volcanic activity has taken the form of fumarolic emanations of variable intensity and temperature,
mainly concentrated at “La Fossa” crater, with maximum temperatures ranging between 200 and 300
C; temperature increases and changes in the gas chemistry, were often observed. The most recent episode began
in the 80’s when fumarole temperature progressively increased to 690C in May 1993. Vulcano is active and this
favoured monitoring and research studies, in particular focussed on the most recent structures.
In the frame of DPC-INGV “V3” project, we investigate the dynamics of the island through ca. 40 years of ground
deformation and seismicity data collected by the discrete and continuous INGV monitoring networks. We considered
levelling, GPS, EDM, seismic and tilt data. EDM and levelling measurements began in the middle 1970s and
since the late 1990s the same EDM network has been surveyed by GPS.
By combining and comparing geodetic data and seismicity we are able to distinguish three different scales of
phenomena: the first one seems to be linked to the regional tectonics, with a general transpressive kinematics;
the second one affects the northern half of the island and could be related to the caldera dynamics; the third one
affects only the cone of La Fossa. Regional tectonic stress seems to play an important role in the transition of the
volcanic system from a phase of stability to a phase of unrest, inducing the heating and the expansion of shallow
hydrothermal fluids. Current local ground deformation at Vulcano may be linked to the geothermal system rather
than magmatic sources.

The shape and stability of a volcano's edifice depends on the relationship between eruption rate and the loss or redistribution of material due to erosion, mass-wasting or deformation. This work provides measurements of deformation and shallow mass-wasting at a stratovolcano immediately after an extended period of growth, and demonstrates that high rates of deformation can be associated with shallow edifice processes. We measure displacements and surface property changes on the upper flanks of Arenal, Costa Rica, after a ~40 year period of edifice growth. We present high-resolution satellite radar imagery of the 2011–2013 period that provides evidence of frequent rockfalls and of at least 16 slow-moving, shallow landslides (estimated to be 5–11 m thick, total volume = 2.4 × 107 m3 DRE). The 2012 Nicoya Earthquake (Mw 7.4) had no measurable impact on the velocities of sliding units at Arenal, but did result in an increase in the area affected by rockfall.

Neapolitan Volcanoes is more than a guide to the world’s most exciting volcanoes: it is a story of how volcanology has grown from an entertainment for Europe’s curious nobility to one of the most fascinating and challenging branches of modern Earth Sciences. It is a story, too, of how people have lived and flourished among the most resplendent and dangerous forces of Nature.
Vesuvius, Campi Flegrei and Ischia: the names alone evoke tales of the growth of European culture from Ancient Greece and Rome to the Grand Tour of the aristocracy in the eighteenth and nineteenth centuries. Even more, the conse- quences of eruptions can be traced back at least 40 millennia, when the eruption of the Campanian Ignimbrite, from within or near Campi Flegrei, heralded the demise of Neanderthals in Europe.
From a volcanological perspective, outbursts from Vesuvius in particular have provided the template for understanding common styles of eruption observed around the world. Most famous is the first written account of the style of explosive eruption that overwhelmed Pompeii and Herculaneum in 79 A.D., now described as Plinian in honour of both Pliny the Younger, who wrote the description, and his uncle Pliny the Elder who, as admiral of the Roman fleet, set sail from Miseno in the Campi Flegrei and died offering succour to those fleeing from the eruption. At the other extreme, sixteen centuries later the rivers of molten rock that oozed from the volcano acquired the name of lava, from the Italian verb lavare, to suggest that the slopes of the volcano had been washed clean.
Watching the volcanoes around Naples also reveals the importance of learning from experience. Between 1764 and 1800, William Hamilton—self-taught volca- nologist and British plenipotentiary to the court in Naples—regularly hosted vis- itors to Vesuvius and Campi Flegrei. Writing to the Royal Society of London in 1779, he commented that he had been to the summit of Vesuvius 58 times and had visited the lower slopes of the volcano at least four times more often. Even so he says “I am not ashamed to own that I comprehend very little of the wonders I have
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x Foreword
seen on this great laboratory of Nature”, adding that “yet there have been natu- ralists, of such a wonderful penetrating genius, as to have thought themselves sufficiently qualified to account for every phenomenon of Vesuvius, after having, literally speaking, given the volcano a coup d’oeil”. The record shows that Hamilton’s understanding far exceeded that of his guests with penetrating genius. Neapolitan Volcanoes follow Hamilton’s principle and underline how we are still learning 250 years later.
The volcanoes today support a population of about one million people, not counting Naples, whose urban sprawl overlaps the Campi Flegrei to the west and reaches the foothills of Vesuvius to the east. Vesuvius has been quiet since 1944, Campi Flegrei since 1538 and Ischia since 1302. No one has a memory of how their local volcanoes behave. This book shows the debt modern volcanology owes to understanding Neapolitan Volcanoes and how such understanding is essential to preparing for when the very same volcanoes will come back to life.

London, UK
Christopher Kilburn UCL Hazard Centre
University College London