A new database of independently estimated eruption source parameters devoted to eruptive column model evaluation

2020 ◽  
Author(s):  
Samantha Engwell ◽  
Thomas Aubry ◽  
Sebastien Biass ◽  
Costanza Bonadonna ◽  
Marcus Bursik ◽  
...  
Keyword(s):  
Source Parameters ◽  
Column Height ◽  
Density Currents ◽  
Atmospheric Conditions ◽  
Multiple Sources ◽  
Eruption Rate ◽  
Additional Information ◽  
Mass Eruption Rate ◽  
Eruptive Column ◽  
Future Events

<p>Eruptive column models are crucial for managing volcanic crises, forecasting future events, and reconstructing past eruptions. Given their central role in volcanology and the large uncertainties weakening their predictions, the evaluation and improvement of these models is critical. Such evaluation is challenging as it requires independent estimates of the main model inputs (e.g. mass eruption rate) and outputs (e.g. column height). Despite recent efforts to extend datasets of independently estimated eruption source parameters (ESP) (e.g. Mastin 2014, Aubry et al. 2017), there is no standardized, maintained, and community-based ESP database devoted to the evaluation of eruptive column models.</p><p>Here we present a new ESP database designed to respond to the needs of the plume modelling community, and which will also be valuable to observatories, field volcanologists, and volcanic ash advisory centers. We compiled data for over 130 eruptive events with independent estimates of: i) the mass eruption rate; ii) the height reached by the column; and iii) atmospheric conditions during the eruption. In contrast with previous ESP datasets, we distinguish estimates of column height that relate to different phases (ash and SO2) and parts of the column (plume top or umbrella). We additionally provide the total grain size distribution, uncertainties in eruption parameters, and multiple sources for atmospheric profiles for events where these parameters are available. The database also includes a wealth of additional information which will enable modelers to distinguish between different eruptions when evaluating or calibrating models. This includes the type of eruption, the morphology of the plume (weak/transitional/strong), and the occurrence and mass entrained within pyroclastic density currents.</p><p>We will apply the new database to revisit empirical scaling relationships between the mass eruption rate and “plume height”. In particular, we will show how such relationships depend on the type of height (e.g. SO2 height vs. ash top height) and eruption (e.g. magmatic vs. phreatomagmatic) considered. We will also discuss the difficulties and limitations of compiling ESP estimates from the literature as well as characterizing fundamentally unsteady volcanic events by a single value for each ESP.</p>

scholarly journals Modelling pyroclastic density currents from a subplinian eruption at La Soufrière de Guadeloupe (West Indies, France)

2020 ◽  
Vol 82 (12) ◽  
Author(s):  
Tomaso Esposti Ongaro ◽  
Jean-Christophe Komorowski ◽  
Yoann Legendre ◽  
Augusto Neri
Keyword(s):  
Hazard Assessment ◽  
High Performance ◽  
Numerical Models ◽  
Probability Distributions ◽  
Dynamic Pressure ◽  
Source Parameters ◽  
Reference Scenario ◽  
Density Currents ◽  
Eruption Rate ◽  
Mass Eruption Rate

AbstractWe have used a three-dimensional, non-equilibrium multiphase flow numerical model to simulate subplinian eruption scenarios at La Soufrière de Guadeloupe (Lesser Antilles, France). Initial and boundary conditions for computer simulations were set on the basis of independent estimates of eruption source parameters (i.e. mass eruption rate, volatile content, temperature, grain size distribution) from a field reconstruction of the 1530 CE subplinian eruption. This event is here taken as a reference scenario for hazard assessment at La Soufrière de Guadeloupe. A parametric study on eruption source parameters allowed us to quantify their influence on the simulated dynamics and, in particular, the increase of the percentage of column collapse and pyroclastic density current (PDC) intensity, at constant mass eruption rate, with variable vent diameter. Numerical results enabled us to quantify the effects of the proximal morphology on distributing the collapsing mass around the volcano and into deep and long valleys and to estimate the areas invaded by PDCs, their associated temperature and dynamic pressure. Significant impact (temperature > 300 °C and dynamic pressure > 1 kPa) in the inhabited region around the volcano is expected for fully collapsing conditions and mass eruption rates > 2 × 107 kg/s. We thus combine this spatial distribution of temperature and dynamic pressure with an objective consideration of model-related uncertainty to produce preliminary PDC hazard maps for the reference scenario. In such a representation, we identify three areas of varying degree of susceptibility to invasion by PDCs—very likely to be invaded (and highly impacted), susceptible to invasion (and moderately impacted), and unlikely to be invaded (or marginally impacted). The study also raises some key questions about the use of deterministic scenario simulations for hazard assessment, where probability distributions and uncertainties are difficult to estimate. Use of high-performance computing techniques will in part allow us to overcome such difficulties, but the problem remains open in a scientific context where validation of numerical models is still, necessarily, an incomplete and ongoing process. Nevertheless, our findings provide an important contribution to the quantitative assessment of volcanic hazard and risk at La Soufrière de Guadeloupe particularly in the context of the current unrest of the volcano and the need to prepare for a possible future reawakening of the volcano that could culminate in a magmatic explosive eruption.

scholarly journals Dynamics and style transition of a moderate, Vulcanian-driven eruption at Tungurahua (Ecuador) in February 2014: pyroclastic deposits and hazard considerations

Solid Earth ◽  
2017 ◽  
Vol 8 (3) ◽  
pp. 697-719 ◽  
Author(s):  
Jorge Eduardo Romero ◽  
Guilhem Amin Douillet ◽  
Silvia Vallejo Vargas ◽  
Jorge Bustillos ◽  
Liliana Troncoso ◽  
...  
Keyword(s):  
Large Scale ◽  
Source Parameters ◽  
Magma Ascent ◽  
Dispersion Pattern ◽  
Density Currents ◽  
Tephra Fall ◽  
Eruptive Column ◽  
2014 Eruption ◽  
Eruptive Cycle ◽  
Tungurahua Volcano

Abstract. The ongoing eruptive cycle of Tungurahua volcano (Ecuador) since 1999 has been characterised by over 15 paroxysmal phases interrupted by periods of relative calm. Those phases included one Subplinian as well as several Strombolian and Vulcanian eruptions and they generated tephra fallouts, pyroclastic density currents (PDCs) and lava flows. The 1 February 2014 eruption occurred after 75 days of quiescence and only 2 days of pre-eruptive seismic crisis. Two short-lived Vulcanian explosions marked the onset of the paroxysmal phase, characterised by a 13.4 km eruptive column and the trigger of PDCs. After 40 min of paroxysm, the activity evolved into sporadic Strombolian explosions with discrete ash emissions and continued for several weeks. Both tephra fall and PDCs were studied for their dispersal, sedimentology, volume and eruption source parameters. At large scale, the tephra cloud dispersed toward the SSW. Based on the field data, two dispersal scenarios were developed forming either elliptical isopachs or proximally PDC-influenced isopachs. The minimum bulk tephra volumes are estimated to 4.55 × 106 m3, for an eruption size estimated at volcanic explosivity index (VEI) 2–3. PDCs, although of small volume, descended by nine ravines of the NNW flanks down to the base of the edifice. The 1 February 2014 eruptions show a similar size to the late 1999 and August 2001 events, but with a higher intensity (I 9–10) and shorter duration. The Vulcanian eruptive mechanism is interpreted to be related to a steady magma ascent and the rise in over-pressure in a blocked conduit (plug) and/or a depressurised solidification front. The transition to Strombolian style is well documented from the tephra fall componentry. In any of the interpretative scenarios, the short-lived precursors for such a major event as well as the unusual tephra dispersion pattern urge for renewed hazard considerations at Tungurahua.

scholarly journals Dynamics and style transition of a moderate, Vulcanian-driven eruption at Tungurahua (Ecuador) on February 2014: pyroclastic deposits and hazard considerations

2016 ◽  
Author(s):  
Jorge Eduardo Romero ◽  
Guilhem Amin Douillet ◽  
Silvia Vallejo Vargas ◽  
Jorge Bustillos ◽  
Liliana Troncoso ◽  
...  
Keyword(s):  
Source Parameters ◽  
Magma Ascent ◽  
Dispersion Pattern ◽  
Density Currents ◽  
Tephra Fall ◽  
Eruptive Column ◽  
2014 Eruption ◽  
Eruptive Cycle ◽  
Bulk Deposit ◽  
Tungurahua Volcano

Abstract. The ongoing eruptive cycle of Tungurahua volcano (Ecuador) since 1999 has been characterized by over 15 paroxysmal phases interrupted by periods of relative calm. Those phases included Strombolians, Vulcanians and one Subplinian eruptions and they generated tephra fallouts, pyroclastic density currents (PDCs) and lava flows. The 01 February 2014 eruption occurred after 75 days of quiescence. Two days before the eruption, a gradual increase of seismicity associated with sporadic weak ash emissions occured. Between 13:30 and 16:30 UTC of the 01 February, a swarm of volcano tectonic and long period earthquakes was detected and announced the possibility of an eruption within hours or days. After a few hours without surface manifestations, two short-lived Vulcanian explosions triggered the paroxysmal phase at 22:39 UTC which lasted 40 min and produced an eruptive column 13.4 km in height sustained during about 9 min. The activity evolved at 23:36 UTC into sporadic Strombolian explosions with discrete ash emissions and continued for several weeks. Both tephra fall and PDCs were studied for their dispersal, sedimentology, volume and eruption source parameters. Tephra was distributed around 240° to the S-SW of the volcano, and the bulk deposit volume is estimated to be 1.53 ± 0.35 × 10−2 km3 (4.76 ± 2.23 × 106 m3 DRE; VEI 3). PDCs descended by 9 ravines of the N-NW flanks. It was one of Tungurahua’s largest eruptions, after the August 2006 Subplinian event. The Vulcanian eruptive mechanism is interpreted to be related to a steady magma ascent and the rise in over-pressure in a blocked conduit (plug) and/or a depressurized solidification front. The transition to Strombolian style is well documented from the tephra fall componentry. In any of the interpretative scenari, the short-lived precursors for such a major event as well as the unusual tephra dispersion pattern urge for renewed hazard considerations at Tungurahua.

Development of an Inverse Plume Model for Mass Eruption Rate in Unsteady Conditions

2021 ◽  
Author(s):  
Stephen A Solovitz
Keyword(s):  
Laboratory Data ◽  
Model Performance ◽  
Volcanic Eruptions ◽  
Reynolds Numbers ◽  
Model Parameters ◽  
Plume Height ◽  
Eruption Rate ◽  
Mass Eruption Rate ◽  
Downstream Effects ◽  
Order Of Magnitude

Abstract Following volcanic eruptions, forecasters need accurate estimates of mass eruption rate (MER) to appropriately predict the downstream effects. Most analyses use simple correlations or models based on large eruptions at steady conditions, even though many volcanoes feature significant unsteadiness. To address this, a superposition model is developed based on a technique used for spray injection applications, which predicts plume height as a function of the time-varying exit velocity. This model can be inverted, providing estimates of MER using field observations of a plume. The model parameters are optimized using laboratory data for plumes with physically-relevant exit profiles and Reynolds numbers, resulting in predictions that agree to within 10% of measured exit velocities. The model performance is examined using a historic eruption from Stromboli with well-documented unsteadiness, again providing MER estimates of the correct order of magnitude. This method can provide a rapid alternative for real-time forecasting of small, unsteady eruptions.

The numerical reconstruction of three past eruptions at Gede volcano (Indonesia)

2021 ◽  
Author(s):  
Eleanor Tennant ◽  
Susanna Jenkins ◽  
Annie Winson ◽  
Christina Widiwijayanti ◽  
Hendra Gunawan ◽  
...  
Keyword(s):  
Epistemic Uncertainty ◽  
Source Parameters ◽  
Frictional Resistance ◽  
Collapse Mechanism ◽  
Eruption Dynamics ◽  
Pyroclastic Density Currents ◽  
Density Currents ◽  
Basal Friction ◽  
Column Collapse ◽  
Hazard And Risk

<p>Understanding past eruption dynamics at a volcano is crucial for forecasting the range of possible future eruptions and their associated hazards and risk. In this work we reconstructed pyroclastic density currents and tephra fall from three eruptions at Gede volcano, Indonesia with the aim of gaining further insight into past eruptions and identifying suitable eruption source parameters for future hazard and risk assessment. Gede has the largest number of people living within 100 km of any volcano worldwide, and has exhibited recent unrest activity, yet little is known about its eruption history. For pyroclastic density currents, we used Titan2D to reconstruct geological deposits dated at 1200 and c. 1000 years BP. An objective and quantitative multi-criteria method was developed to evaluate the fit of over 300 pyroclastic density current (PDC) model simulations to field observations. We found that the 1200 years BP geological deposits could be reproduced with either a dome collapse or column collapse as the generation mechanism although a relatively low basal friction of 6 degrees would suggest that the PDCs were markedly mobile. Lower basal frictions may reflect the occurrence of previous PDCs that smoothed the path, reducing frictional resistance and enabling greater runout for the reconstructed unit. For the 1,000 years BP PDC, a column collapse mechanism and higher basal friction was required to fit the geological deposits. In agreement with previous studies, we found that Titan2D simulations were most sensitive to the basal friction; however, we also found that the internal friction – often fixed and considered of low influence on outputs - can have a moderate effect on the simulated average deposit thickness. We used Tephra2 to reconstruct historic observations of tephra dispersed to Jakarta and other towns during the last known magmatic eruption of Gede in 1948. In the absence of observable field deposits, or detailed information from the published literature, we stochastically sampled eruption source parameters from wide ranges informed by analogous volcanic systems. Our modelling suggests that the deposition of tephra in Jakarta during the November 1948 eruption was a very low probability event, with approximately a 0.03 % chance of occurrence. Through this work, we exemplify the reconstruction of past eruptions when faced with epistemic uncertainty, and improve our understanding of past eruption dynamics at Gede volcano, providing a crucial step towards the reduction of risk to nearby populations through volcanic hazard assessment.</p>

scholarly journals Interferometric hydrofracture microseism localization using neighboring fracture

Geophysics ◽  
2011 ◽  
Vol 76 (6) ◽  
pp. WC27-WC36 ◽  
Author(s):  
Oleg V. Poliannikov ◽  
Alison E. Malcolm ◽  
Hugues Djikpesse ◽  
Michael Prange
Keyword(s):  
Signal To Noise Ratio ◽  
Common Source ◽  
Square Root ◽  
Multiple Sources ◽  
Multiple Fractures ◽  
Additional Information ◽  
Monitoring Well ◽  
Receiver Array ◽  
Second Fracture ◽  
Available Information

Hydraulic fracturing is the process of injecting high-pressure fluids into a reservoir to induce fractures and thus improve reservoir productivity. Microseismic event localization is used to locate created fractures. Traditionally, events are localized individually. Available information about events already localized is not used to help estimate other source locations. Traditional localization methods yield an uncertainty that is inversely proportional to the square root of the number of receivers. However, in applications where multiple fractures are created, multiple sources in a reference fracture may provide redundant information about unknown events in subsequent fractures that can boost the signal-to-noise ratio, improving estimates of the event positions. We used sources in fractures closer to the monitoring well to help localize events further away. It is known through seismic interferometry that with a 2D array of receivers, the traveltime between two sources may be recovered from a crosscorrelogram of two common source gathers. This allowed an event in the second fracture to be localized relative to an event in the reference fracture. A difficulty became evident when receivers are located in a single monitoring well. When the receiver array is 1D, classical interferometry cannot be directly employed because the problem becomes underdetermined. In our approach, interferometry was used to partially redatum microseismic events from the second fracture onto the reference fracture so that they can be used as virtual receivers, providing additional information complementary to that provided by the physical receivers. Our error analysis showed that, in addition to the gain obtained by having multiple physical receivers, the location uncertainty is inversely proportional to the square root of the number of sources in the reference fracture. Because the number of microseism sources is usually high, the proposed method will usually result in more accurate location estimates as compared with the traditional methods.

scholarly journals Adaptive Source Location Estimation Based on Compressed Sensing in Wireless Sensor Networks

2012 ◽  
Vol 8 (1) ◽  
pp. 592471 ◽  
Author(s):  
Lei Liu ◽  
Jin-Song Chong ◽  
Xiao-Qing Wang ◽  
Wen Hong
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Compressed Sensing ◽  
Source Parameters ◽  
Location Estimation ◽  
Multiple Source ◽  
Wireless Sensor ◽  
Multiple Sources ◽  
Redundant Dictionary ◽  
Speed Up

Source localization is an important problem in wireless sensor networks (WSNs). An exciting state-of-the-art algorithm for this problem is maximum likelihood (ML), which has sufficient spatial samples and consumes much energy. In this paper, an effective method based on compressed sensing (CS) is proposed for multiple source locations in received signal strength-wireless sensor networks (RSS-WSNs). This algorithm models unknown multiple source positions as a sparse vector by constructing redundant dictionaries. Thus, source parameters, such as source positions and energy, can be estimated by [Formula: see text]-norm minimization. To speed up the algorithm, an effective construction of multiresolution dictionary is introduced. Furthermore, to improve the capacity of resolving two sources that are close to each other, the adaptive dictionary refinement and the optimization of the redundant dictionary arrangement (RDA) are utilized. Compared to ML methods, such as alternating projection, the CS algorithm can improve the resolution of multiple sources and reduce spatial samples of WSNs. The simulations results demonstrate the performance of this algorithm.

scholarly journals Design of parametric risk transfer solutions for volcanic eruptions: an application to Japanese volcanoes

2021 ◽  
Vol 21 (1) ◽  
pp. 99-113
Author(s):  
Delioma Oramas-Dorta ◽  
Giulio Tirabassi ◽  
Guillermo Franco ◽  
Christina Magill
Keyword(s):  
Financial Risk ◽  
Volcanic Eruptions ◽  
Transfer Mechanism ◽  
Column Height ◽  
Regional Government ◽  
Building Structures ◽  
Risk Transfer ◽  
Natural Catastrophes ◽  
Ash Fall ◽  
Eruptive Column

Abstract. Volcanic eruptions are rare but potentially catastrophic phenomena, affecting societies and economies through different pathways. The 2010 Eyjafjallajökull eruption in Iceland, a medium-sized ash-fall-producing eruption, caused losses in the range of billions of dollars, mainly to the aviation and tourism industries. Financial risk transfer mechanisms such as insurance are used by individuals, companies, governments, etc., to protect themselves from losses associated with natural catastrophes. In this work, we conceptualize and design a parametric risk transfer mechanism to offset losses to building structures arising from large, ash-fall-producing volcanic eruptions. Such a transfer mechanism relies on the objective measurement of physical characteristics of volcanic eruptions that are correlated with the size of resulting losses (in this case, height of the eruptive column and predominant direction of ash dispersal) in order to pre-determine payments to the risk cedent concerned. We apply this risk transfer mechanism to the case of Mount Fuji in Japan by considering a potential risk cedent such as a regional government interested in offsetting losses to dwellings in the heavily populated prefectures of Tokyo and Kanagawa. The simplicity in determining eruptive column height and ash fall dispersal direction makes this design suitable for extrapolation to other volcanic settings worldwide where significant ash-fall-producing eruptions may occur, provided these parameters are reported by an official, reputable agency and a suitable loss model is available for the volcanoes of interest.

scholarly journals Improved finite-source inversion through joint measurements of rotational and translational ground motions: A theoretical study

2016 ◽  
Author(s):  
Michael Reinwald ◽  
Moritz Bernauer ◽  
Heiner Igel ◽  
Stefanie Donner
Keyword(s):  
Inverse Problem ◽  
Ground Motions ◽  
Source Parameters ◽  
Normal Fault ◽  
Seismic Source ◽  
Vertical Gradient ◽  
Vertical Displacement ◽  
Source Inversion ◽  
Additional Information ◽  
Finite Source

Abstract. With the prospects of seismic equipment being able to measure rotational ground motions in a wide frequency and amplitude range in the near future we engage in the question how this type of ground motion observation can be used to solve the seismic inverse problem. In this paper, we focus on the question, whether finite source inversion can benefit from additional observations of rotational motion. Keeping the overall number of traces constant, we compare observations from a surface seismic network with 44 3-component translational sensors (classic seismometers) with those obtained with 22 6-component sensors (with additional 3-component rotational motions). Synthetic seismograms are calculated for known finite-source properties. The corresponding inverse problem is posed in a probabilistic way using the Shannon information content as measure how the observations constrain the seismic source properties. We minimize the influence of the source receiver geometry around the fault by statistically analyzing six-component (three velocity and three rotation rate) inversions with a random distribution of receivers. The results show that with the 6-C subnetworks the source properties are not only equally well recovered (even that would be benefitial because of the substantially reduced logistics installing half the sensors) but statistically some source properties are almost always better resolved. We assume that this can be attributed to the fact that the (in particular vertical) gradient information is contained in the additional motion components. We compare these effects for strike-slip and normal-faulting type sources and confirm that the increase in inversion quality for kinematic source parameters is even higher for the normal fault. This indicates that the inversion benefits from the additional information provided by the horizontal rotation rates, i.e. information about the vertical displacement gradient.

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