Search results for "Eruption"

Rapid laccolith intrusion driven by explosive volcanic eruption

2016

Magmatic intrusions and volcanic eruptions are intimately related phenomena. Shallow magma intrusion builds subsurface reservoirs that are drained by volcanic eruptions. Thus, the long-held view is that intrusions must precede and feed eruptions. Here we show that explosive eruptions can also cause magma intrusion. We provide an account of a rapidly emplaced laccolith during the 2011 rhyolite eruption of Cordón Caulle, Chile. Remote sensing indicates that an intrusion began after eruption onset and caused severe (>200 m) uplift over 1 month. Digital terrain models resolve a laccolith-shaped body ∼0.8 km3. Deformation and conduit flow models indicate laccolith depths of only ∼20–200 m and ov…

Hot-spot detection and characterization of strombolian activity from MODIS infrared data

2014

Identifying and characterizing strombolian activity from space is a challenging task for satellite-based infrared systems. Stromboli volcano is a natural laboratory that offers a unique opportunity for refining thermal remote-sensing applications that involve transient phenomena and small to moderate hot-spots. A new simple and fast algorithm gave us the opportunity to revisit the MODIS-derived thermal output at Stromboli volcano over the last 13 years. The new algorithm includes both night-time and daytime data and shows high performance with the detection of small-amplitude thermal anomalies (  1000 MW). The ...

Practical Volcano-Independent Recognition of Seismic Events: VULCAN.ears Project

2021

Recognizing the mechanisms underlying seismic activity and tracking temporal and spatial patterns of earthquakes represent primary inputs to monitor active volcanoes and forecast eruptions. To quantify this seismicity, catalogs are established to summarize the history of the observed types and number of volcano-seismic events. In volcano observatories the detection and posterior classification or labeling of the events is manually performed by technicians, often suffering a lack of unified criteria and eventually resulting in poorly reliable labeled databases. State-of-the-art automatic Volcano-Seismic Recognition (VSR) systems allow real-time monitoring and consistent catalogs. VSR systems…

Groundwater radon measurements in the Mt. Etna area.

2003

Radon levels were measured in 119 groundwater samples collected throughout the active volcanic area of Mt. Etna by means of a portable Lucas-type scintillation chamber. The measured activity values range from 1.8 to 52.7 Bq l(-1). About 40% of the samples exceed the maximum contaminant level of 11 Bq l(-1) proposed by the USEPA in 1991. The highest radon levels are measured in the eastern sector of the volcano, which is the seismically most active zone of the volcano. On the contrary the south-western sector, which is both seismically active and a site of intense magmatic degassing, display lower radon levels. This is probably due to the formation of a free gas phase (oversaturation of CO(2…

On the occurrence of ClO in cirrus clouds and volcanic aerosol in the tropopause region

1997

Airborne observations during descents of the ER-2 through layers of volcanic aerosol (Mount Pinatubo eruption of 1991) and a cirrus cloud are utilized to study the the abundance of ClO and its relation to aerosol surface area in the midlatitude tropopause region. During a cirrus event near the tropopause ClO mixing ratios up to 2.7 pptv were detected and near the tropopause ClO levels from a few to 70 pptv were found. These measurements are associated with large experimental uncertainties but demonstrate the possible presence of ClO inside cirrus clouds and near the tropopause. Model calculations show that possible enhancements of ClO by heterogeneous chemistry on cirrus cloud particles cou…

Conduit dynamics and post explosion degassing on Stromboli: A combined UV camera and numerical modeling treatment

2016

Recent gas flux measurements have shown that Strombolian explosions are often followed by periods of elevated flux, or “gas codas,” with durations of order a minute. Here we present UV camera data from 200 events recorded at Stromboli volcano to constrain the nature of these codas for the first time, providing estimates for combined explosion plus coda SO2 masses of ≈18–225 kg. Numerical simulations of gas slug ascent show that substantial proportions of the initial gas mass can be distributed into a train of “daughter bubbles” released from the base of the slug, which we suggest, generate the codas, on bursting at the surface. This process could also cause transitioning of slugs into cap b…

First gas flux measurements of conduit permeability decrease prior to Strombolian eruption at Stromboli volcano (Italy)

2016

Strombolian eruptions can be described in terms of growth, coalescence, and rise of a gas pocket (aka slug) bursting at the surface of a vent. This model overlooks that the transition to explosive regimes is mostly controlled by the permeability in the upper part of a volcanic conduit. We report here on the first gas flux measurements of Strombolian explosions from a vent that exhibited a significant decrease of passive degassing tens of second prior to the onset of the explosion. This particular explosive activity took place during the July 2014 lava overflows, when the magma level inside the conduit rose up to the crater terrace. The amount of gas that accumulated before the eruption is i…

Biometric study about dimension of ectopic buccal maxillary canines

2011

Exploring the explosive‐effusive transition using permanent ultra‐violet cameras

2017

Understanding the mechanisms that cause effusive eruptions is the key to mitigating their associated hazard. Here we combine results from permanent ultraviolet (UV) cameras, and from other geophysical observations (seismic very long period, thermal, and infrasonic activity), to characterize volcanic SO2 flux regime in the period prior, during, and after Stromboli's August–November 2014 effusive eruption. We show that, in the 2 months prior to effusion onset, the SO2 flux levels are 2 times average level. We explain this anomalously high SO2 regime as primarily determined by venting of rapidly rising, pressurized SO2-rich gas pockets produced by strombolian explosions being more frequent and…

A rare complication of idiopathic osteosclerosis

2007

Idiopathic osteosclerosis (IO) is described as a localized no expansible radiopacity with unknown etiology. The IO is generally asymptomatic and could appear as round, elliptical or irregular in shape. The internal aspect is usually uniformly radiopaque. IO should be distinguished from condensing osteitis of dental origin, or other alveolar bone related radiopacities such as periapical cemental dysplasia. This condition may cause changes in tooth position or problems during orthodontic treatment. The purpose of the present study is to report a case of tooth resorption caused by ectopic eruption rote caused by IO. This condition represents a rare complication of IO.