Stability analysis and tsunamigenic mass-failure scenarios in Palinuro volcano complex, Tyrrhenian sea

Author(s):  
Glauco Gallotti ◽  
Guido Ventura ◽  
Alberto Armigliato ◽  
Filippo Zaniboni ◽  
Gianluca Pagnoni ◽  
...  

<p>The Palinuro volcanic chain is located nearly 80 km offshore the Campania coasts (Italy), in the southern sector of the Tyrrhenian Sea. As many as 15 distinct volcanic edifices have been recently detected that covers a 90 km long and 20 km wide belt. The associated volcanism is still poorly understood but the presence of shallow seismicity and active hydrothermal activity suggest that this large volcanic complex is still active. Specific sectors of the chain show the presence of ongoing slope instability and thus the chance of mass movements cannot be ruled out in case of seismic or volcanic activity. In this work, a stability analysis for typical seismic loads in such a volcanic area has been performed through a revised limit equilibrium approach. In the revealed weaker sections, three mass failures of different scales have been reconstructed and their motion has been calculated by means of numerical models. The tsunami produced by each slide has been simulated, and considerable waves have been found in two of the three hypothesized scenarios. For the biggest slide of 2.4 km<sup>3</sup>, waves as high as 10 m could reach portions of the Calabria coasts with consequent hazardous impact.</p><p>This study belongs to a series of works focused on the volcanoes of the Tyrrhenian Sea that are very many and still poorly investigated. Considering scenarios involving mass movements of different sizes with distinct characteristics and based on geomorphological features seems to be a viable strategy to evaluate the tsunami hazard in the region.  </p>

2020 ◽  
Vol 83 (1) ◽  
Author(s):  
G. Gallotti ◽  
F. Zaniboni ◽  
G. Pagnoni ◽  
C. Romagnoli ◽  
F. Gamberi ◽  
...  

AbstractThe Marsili Seamount (Tyrrhenian Sea, Italy) is the largest submarine volcano in the Mediterranean Sea, located in the middle of the Marsili Basin, facing the Calabrian and Sicilian coasts on its eastern side, and the coasts of Sardinia on the opposite side. It has erupted in historical times, and its summit crest is affected by widespread hydrothermal activity. This study looks at mass failures taking place at different depths on the flanks of the volcano and estimates their associated tsunamigenic potential. Mass failure, tsunami generation, and propagation have been simulated by means of numerical models developed by the Tsunami Research Team of the University of Bologna. In all, we consider five cases. Of these, three scenarios, one regarding a very small detachment and two medium-sized ones (between 2 and 3 km3 failure volume), have been suggested as possible failure occurrences in the published literature on a morphological basis and involve the north-eastern and north-western sectors of the volcano. The two additional cases, one medium-sized and one extreme, intended as a possible worst-case scenario (volume 17.6 km3), affecting the eastern flank. Results indicate that small-volume failures are not able to produce significant tsunamis; medium-size failures can produce tsunamis which dangerously affect the coasts if their detachment occurs in shallow water, i.e., involves the volcano crest; and extreme volume failures have the potential to create disastrous tsunamis. In all the simulations, tsunami waves appear to reach the Aeolian Islands in around 10 min and the coasts of Calabria and Sicily in 20 min. This study highlights that there is a potential for dangerous tsunamis generation from collapses of the Marsili volcano and as a consequence a need to intensify research on its status and stability conditions. More broadly, this investigation should also be extended to the other volcanic seamounts of the Tyrrhenian Sea, since their eruptive style, evolution, and tsunamigenic potential are still poorly known.


2005 ◽  
Vol 5 (3) ◽  
pp. 367-374 ◽  
Author(s):  
I. Baron ◽  
F. Agliardi ◽  
C. Ambrosi ◽  
G. B. Crosta

Abstract. Deep-seated slope failures are common features in the mountains of the Raca Unit, Magura Nappe of the Flysch Belt of Western Carpathians. Since they represent very complicated system, understanding of their evolution and triggers still remains unclear. We tried to provide a back-analysis of their development by using a finite difference code (FDM) of continua (Flac 4.0). We confirmed that such large mass movements could be triggered by water saturation of the bedrock in the three particular geological and geomorphic settings. Such situation could have been caused by heavy rainfalls in humid phases of the Holocene or permafrost melting in Late Glacial. The effects of faulting, very deep weathering of the bedrock, low geotechnical parameters of smectite-rich material and the local slope geometry have also been accounted for in numerical models, as well as the other triggering factors of slope instability. FDM modelled shear zones are in agreement with observations.


2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Valentina Esposito ◽  
Simonepietro Canese ◽  
Gianfranco Scotti ◽  
Marzia Bo ◽  
Cinzia De Vittor ◽  
...  

AbstractSpiculosiphon oceana Maldonado, López-Acosta, Sitjà, Aguilar, García & Vacelet, 2013 is a Mediterranean endemic giant stalked foraminifer described as a potential bio-indicator of acidic environments, thanks to its ability to cope with stressful chemical conditions. Here, we present the first record and the first video images of living specimens of this giant foraminifera in the Panarea Volcanic Complex (PVC; southern Tyrrhenian Sea), representing the third discovery worldwide. Specimens of S. oceana were identified through microscopic and remotely operated vehicle (ROV) image analyses, in two different areas characterised by water column physico-chemical parameters typical of the non-vented areas, but with some evidence of hydrothermal alteration. This new finding enhances knowledge on the ecology of S. oceana, enlarges its known spatial distribution, and corroborates its affinity to intermediate stress conditions related to hydrothermal activity.


1980 ◽  
Vol 17 (4) ◽  
pp. 607-612 ◽  
Author(s):  
Luis E. Vallejo

A new approach to the stability analysis of thawing slopes at shallow depths, taking into consideration their structure (this being a mixture of hard crumbs of soil and a fluid matrix), is presented. The new approach explains shallow mass movements such as skin flows and tongues of bimodal flows, which usually take place on very low slope inclinations independently of excess pore water pressures or increased water content in the active layer, which are necessary conditions in the methods available to date to explain these movements.


2013 ◽  
Vol 275-277 ◽  
pp. 1423-1426
Author(s):  
Lin Kuang ◽  
Ai Zhong Lv ◽  
Yu Zhou

Based on finite element analysis software ANSYS, slope stability analysis is carried out by Elastic limiting equilibrium method proposed in this paper. A series of sliding surface of the slope can be assumed firstly, and then stress field along the sliding surface is analyzed as the slope is in elastic state. The normal and tangential stresses along each sliding surface can be obtained, respectively. Then the safety factor for each slip surface can be calculated, the slip surface which the safety factor is smallest is the most dangerous sliding surface. This method is different from the previous limit equilibrium method. For the previous limit equilibrium method, the normal and tangential stresses along the sliding surface are calculated based on many assumptions. While, the limit equilibrium method proposed in this paper has fewer assumptions and clear physical meaning.


2018 ◽  
Vol 10 (12) ◽  
pp. 2025 ◽  
Author(s):  
Lianhuan Wei ◽  
Yun Zhang ◽  
Zhanguo Zhao ◽  
Xiaoyu Zhong ◽  
Shanjun Liu ◽  
...  

The mining waste of open pit mines is usually piled-up in dump sites, making a man-made hill more than tens of meters high. Because of the loose structure of the dump sites, landslides or debris flow may occur after heavy rainfall, threatening local lives and properties. Therefore, dump stability analysis is crucial for ensuring local safety. In this paper, a collaborative stability analysis based on multiple remote sensing technologies was innovatively conducted at the Xudonggou dump of the Anqian iron mine. A small baseline subset (SBAS) analysis was used to derive the spatial and temporal distributions of displacements in the line-of sight (LOS) over the whole study area. The deformation in LOS is translated to the slope direction based on an assumption that displacements only occur parallel to the slope surface. Infrared Thermography (IRT) technology was used to detect weak aquifer layers located at the toe of possible landslide bodies. Then, numerical simulations based on the limit equilibrium method were conducted to calculate the factor of safety for three profiles located on the dump site. The results, emerging from multiple remote sensing technologies, were very consistent and, eventually, the landslide hazard zone of the Xudonggou dump site was outlined.


2000 ◽  
Vol 22 ◽  
Author(s):  
Giannantonio Bottino ◽  
Giuseppe Mandrone ◽  
Daniela Torta ◽  
Bartolomeo Vigna

In the hilly area of Langa, which is situated to the south of the city of Alba between the Belbo and Bormida Valleys, the heavy rainfall and subsequent floods of 3-6 November 1994 triggered numerous landslides. The slides caused serious damage to residential areas and various types of infrastructure. Engineering geological, geomorphological, geotechnical, hydrogeological, and geophysical methods were applied to investigate the instabilities. Among hundreds of failures, most of them were planar slides and debris-mud flows. However, the numerous landslides directly connected to the event represent only a part of the large and varied types of phenomenon in this area. In fact, most of the recent landslides can be considered as reactivated older ones that were more-or-less quiescent. They intersect at the depth the marly basement and are directly connected to the recent geological and tectonic evolution of the area. The paper describes the mass movements and their causative factors. It also focuses on the hazards and risks associated with the instabilities, and their mitigation measures.


Eos ◽  
2019 ◽  
Vol 100 ◽  
Author(s):  
Terri Cook

Researchers have identified a previously unknown volcanic-intrusive complex that originated through the melting of mantle material at the northern edge of the Ionian slab.


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