scholarly journals Experimental multiblast craters and ejecta — seismo-acoustics, jet characteristics, craters, and ejecta deposits and implications for volcanic explosions

2022 ◽  
Author(s):  
Ingo Sonder ◽  
Alison Graettinger ◽  
Tracianne Neilsen ◽  
Robin Matoza ◽  
Jacopo Taddeucci ◽  
...  
Keyword(s):  
Seismic Energy ◽  
Volcanic Eruptions ◽  
Maximum Size ◽  
Seismic Signal ◽  
Energy Estimates ◽  
First Order ◽  
Blast Energy ◽  
Jet Characteristics ◽  
Volcanic Explosions ◽  
Explosion Depth

Blasting experiments were performed that investigate multiple explosions that occur in quick succession in the ground and their effects on host material and atmosphere. Such processes are known to occur during volcanic eruptions at various depths, lateral locations, and energies. The experiments follow a multi-instrument approach in order to observe phenomena in the atmosphere and in the ground, and measure the respective energy partitioning. The experiments show significant coupling of atmospheric (acoustic)- and ground (seismic) signal over a large range of (scaled)distances (30--330\m, 1--10\(\m\J^{-1/3}\)). The distribution of ejected material strongly depends on the sequence of how the explosions occur. The overall crater sizes are in the expected range of a maximum size for many explosions and a minimum for one explosion at a given lateral location. The experiments also show that peak atmospheric over-pressure decays exponentially with scaled depth at a rate of \bar{d}_0 = 6.47x10^{-4} mJ^{-1/3}; at a scaled explosion depth of \(4x10^{-3} mJ^{-1/3} ca. 1% of the blast energy is responsible for the formation of the atmospheric pressure pulse; at a more shallow scaled depth of 2.75x10^{-3 \mJ^{-1/3} this ratio lies at ca. 5.5–7.5%. A first order consideration of seismic energy estimates the sum of radiated airborne and seismic energy to be up to 20\% of blast energy.

Seeing and hearing quasi-static shear band localization in a sandstone

2021 ◽  
Author(s):  
Alexis Cartwright-Taylor ◽  
Ian G. Main ◽  
Ian B. Butler ◽  
Florian Fusseis ◽  
Maria-Daphne Mangriotis ◽  
...  
Keyword(s):  
Shear Band ◽  
Structural Damage ◽  
Fault Plane ◽  
Acoustic Emissions ◽  
Volcanic Eruptions ◽  
Energy Estimates ◽  
Driving Mechanism ◽  
Time Resolved ◽  
X Ray ◽  
Experimental Apparatus

<p>The localisation of structural damage, in the form of faults and fractures, along a distinct and emergent fault plane is the key driving mechanism for catastrophic failure in the brittle Earth. However, due to the speed at which stable crack growth transitions to dynamic rupture, the precise mechanisms involved in localisation as a pathway to fault formation remain unknown. Understanding these mechanisms is critical to understanding and forecasting earthquakes, including induced seismicity, landslides and volcanic eruptions, as well as failure of man-made materials and structures. We used time-resolved synchrotron x-ray microtomography to image in-situ damage localisation at the micron scale and at bulk axial strain rates down to 10<sup>-7</sup> s<sup>-1</sup>. By controlling the rate of micro-fracturing events during a triaxial deformation experiment, we deliberately slowed the strain localisation process from seconds to minutes as failure approached. This approach, originally established to indirectly image fault nucleation and propagation with acoustic emissions, is completely novel in synchrotron x-ray microtomography and has enabled us to image directly processes that are normally too transient even for fast synchrotron imaging methods. Here, we first present the experimental apparatus and control system used to acquire the data, followed by damage localisation and shear zone development in a sample of Clashach sandstone viewed in unprecedented detail. Time-resolved microtomography images demonstrate a strong intrinsic correlation between shear and dilatant strain in the localised zone, with bulk shear strain accomodated by the nucleation and rotation of en-echelon tensile microcracks within a grain-scale shear band. Rotation is accompanied by antithetic to synthetic shear sliding of neighbouring crack surfaces as they rotate. The evolving 4D strain field, measured with incremental digital volume correlation between pairs of recorded x-ray tomographic volumes, independently confirm the correlation between shear and dilatant strain and show how strain localises spontaneously, first through exploration of several competing shear bands at peak stress before transitioning to failure along the optimally-oriented final fault plane. In order to ‘ground-truth’ inferences made from bulk measurements and seismic waves (the primary method of detecting deformation at the field-scale where direct imaging of the subsurface is impossible), we (a) compare rupture energy estimates from local slip measurements with those from bulk slip data, and (b) use AE source location estimates to identify individual cracks and other local changes in the microstucture that may explain the AE source.</p>

Forecast of the Pyroclastic Volume by Precursory Seismicity of Merapi Volcano

2019 ◽  
Vol 14 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Masato Iguchi ◽  
Haruhisa Nakamichi ◽  
Kuniaki Miyamoto ◽  
Makoto Shimomura ◽  
I Gusti Made Agung Nandaka ◽  
...  
Keyword(s):  
Seismic Energy ◽  
Volcanic Eruptions ◽  
Pyroclastic Flows ◽  
Energy Calculation ◽  
Cumulative Energy ◽  
Merapi Volcano ◽  
Tectonic Earthquakes ◽  
Order Of Magnitude ◽  
The Difference ◽  
Log Linear

We propose a method to evaluate the potential volume of eruptive material using the seismic energy of volcanic earthquakes prior to eruptions of Merapi volcano. For this analysis, we used well-documented eruptions of Merapi volcano with pyroclastic flows (1994, 1997, 1998, 2001, 2006, and 2010) and the rates and magnitudes of volcano-tectonic A-type, volcano-tectonic B-type, and multiphase earthquakes before each of the eruptions. Using the worldwide database presented by White and McCausland [1], we derived a log-linear formula that describes the upper limit of the potential volume of erupted material estimated from the cumulative seismic energy of distal volcano-tectonic earthquakes. The relationship between the volume of pyroclastic material and the cumulative seismic energy released in 1994, 1997, 1998, 2001, 2006, and 2010 at Merapi volcano is well-approximated by the empirical formula derived from worldwide data within an order of magnitude. It is possible to expand this to other volcanic eruptions with short (< 30 years) inter-eruptive intervals. The difference in the intruded and extruded volumes between intrusions and eruptions, and the selection of the time period for the cumulative energy calculation are problems that still need to be addressed.

scholarly journals Experimental multiblast craters and ejecta - seismo-acoustics, jet characteristics, craters, and ejecta deposits and implications for volcanic explosions

2022 ◽  
Author(s):  
Ingo Sonder ◽  
Allison Graettinger ◽  
Tracianne B. Neilsen ◽  
Robin S. Matoza ◽  
Jacopo Taddeucci ◽  
...  
Keyword(s):  
Jet Characteristics ◽  
Volcanic Explosions

scholarly journals Volcanic Tremor of Mt. Etna (Italy) Recorded by NEMO-SN1 Seafloor Observatory: A New Perspective on Volcanic Eruptions Monitoring

Geosciences ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 115
Author(s):  
Tiziana Sgroi ◽  
Giuseppe Di Grazia ◽  
Paolo Favali
Keyword(s):  
Gravity Waves ◽  
Volcanic Tremor ◽  
Volcanic Eruptions ◽  
Seismic Signal ◽  
High Amplitude ◽  
Sea Waves ◽  
Spectral Content ◽  
Mt Etna ◽  
New Perspective ◽  
Seafloor Observatory

The NEMO-SN1 seafloor observatory, located 2100 m below sea level and about 40 km from Mt. Etna volcano, normally records a background seismic signal called oceanographic noise. This signal is characterized by high amplitude increases, lasting up to a few days, and by two typical 0.1 and 0.3 Hz frequencies in its spectrum. Particle motion analysis shows a strong E-W directivity, coinciding with the direction of sea waves; gravity waves induced by local winds are considered the main source of oceanographic noise. During the deployment of NEMO-SN1, the vigorous 2002–2003 Mt. Etna eruption occurred. High-amplitude background signals were recorded during the explosive episodes accompanying the eruption. The spectral content of this signal ranges from 0.1 to 4 Hz, with the most powerful signal in the 0.5–2 Hz band, typical of an Etna volcanic tremor. The tremor recorded by NEMO-SN1 shows a strong NW-SE directivity towards the volcano. Since the receiver is underwater, we inferred the presence of a circulation of magmatic fluids extended under the seafloor. This process is able to generate a signal strong enough to be recorded by the NEMO-SN1 seafloor observatory that hides frequencies linked to the oceanographic noise, permitting the offshore monitoring of the volcanic activity of Mt. Etna.

Weakly stable hyperbolic boundary problems with large oscillatory coefficients: Simple cascades

2020 ◽  
Vol 17 (01) ◽  
pp. 141-183 ◽  
Author(s):  
Mark Williams
Keyword(s):  
Exact Solutions ◽  
Approximate Solutions ◽  
Energy Estimates ◽  
Time Interval ◽  
Geometric Optics ◽  
Zeroth Order ◽  
Boundary Problems ◽  
First Order ◽  
Weakly Stable ◽  
Hyperbolic Boundary

We prove energy estimates for exact solutions to a class of linear, weakly stable, first-order hyperbolic boundary problems with “large”, oscillatory, zeroth-order coefficients, that is, coefficients whose amplitude is large, [Formula: see text], compared to the wavelength of the oscillations, [Formula: see text]. The methods that have been used previously to prove useful energy estimates for weakly stable problems with oscillatory coefficients (e.g. simultaneous diagonalization of first-order and zeroth-order parts) all appear to fail in the presence of such large coefficients. We show that our estimates provide a way to “justify geometric optics”, that is, a way to decide whether or not approximate solutions, constructed for example by geometric optics, are close to the exact solutions on a time interval independent of [Formula: see text]. Systems of this general type arise in some classical problems of “strongly nonlinear geometric optics” coming from fluid mechanics. Special assumptions that we make here do not yet allow us to treat the latter problems, but we believe the present analysis will provide some guidance on how to attack more general cases.

Zero- and first-order approximations for least-squares estimation of seismic signal with coherent and random noise

2010 ◽  
Vol 7 (1) ◽  
pp. 51-63 ◽  
Author(s):  
Yuriy Tyapkin ◽  
Bjorn Ursin ◽  
Herve Perroud ◽  
Olena Silinska ◽  
Olena Tiapkina
Keyword(s):  
Least Squares ◽  
Random Noise ◽  
Seismic Signal ◽  
Least Squares Estimation ◽  
First Order

Seismic attenuation of Atlantic margin basalts: Observations and modeling

Geophysics ◽  
2006 ◽  
Vol 71 (6) ◽  
pp. B211-B221 ◽  
Author(s):  
Jennifer Maresh ◽  
Robert S. White ◽  
Richard W. Hobbs ◽  
John R. Smallwood
Keyword(s):  
Seismic Energy ◽  
Seismic Signal ◽  
Seismic Profile ◽  
Seismic Attenuation ◽  
Thin Layers ◽  
Seismic Survey ◽  
Rock Properties ◽  
Intrinsic Attenuation ◽  
High Impedance ◽  
1D Modeling

Paleogene basalts are present over much of the northeastern Atlantic European margin. In regions containing significant thicknesses of layered basalt flows, conducting seismic imaging within and beneath the volcanic section has proven difficult, largely because the basalts severely attenuate and scatter seismic energy. We use data from a vertical seismic profile (VSP) from well 164/07-1 that penetrated [Formula: see text] of basalt in the northern Rockall Trough west of Britain to measure the seismic attenuation caused by the in-situ basalts. The effective quality factor [Formula: see text] of the basalt layer is found from the VSP to be 15–35, which is considerably lower (more attenuative) than the intrinsic attenuation measured on basalt samples in the laboratory. We then run synthetic seismogram models to investigate the likely cause of the attenuation. Full waveform 1D modeling of stacked sequences of lava flows based on rock properties from the same well indicates that much of the seismic attenuation observed from the VSP can be accounted for by the scattering effects of multiple thin layers with high impedance contrasts. Phase-screen seismic modeling of the rugose basalt surface at the top-of-basalt sediment interface, with the magnitude and wavelength of the relief constrained by a 3D seismic survey around the well, suggests that surface scattering from this interface plays a much smaller role than internal scattering in attenuating the seismic signal as it passes through the basalt sequence.

scholarly journals Accelerometer Sensor Specifications to Predict Hydrocarbon Using Passive Seismic Technique

2016 ◽  
Vol 2016 ◽  
pp. 1-28 ◽  
Author(s):  
M. H. Md Khir ◽  
Atul Kumar ◽  
Wan Ismail Wan Yusoff
Keyword(s):  
Oil And Gas ◽  
Optimal Solution ◽  
Seismic Energy ◽  
Oil And Gas Industry ◽  
Seismic Signal ◽  
Accelerometer Sensor ◽  
Low Frequencies ◽  
Technological Gap ◽  
Passive Seismic ◽  
Seismic Acquisition

The ambient seismic ground noise has been investigated in several surveys worldwide in the last 10 years to verify the correlation between observed seismic energy anomalies at the surface and the presence of hydrocarbon reserves beneath. This is due to the premise that anomalies provide information about the geology and potential presence of hydrocarbon. However a technology gap manifested in nonoptimal detection of seismic signals of interest is observed. This is due to the fact that available sensors are not designed on the basis of passive seismic signal attributes and mainly in terms of amplitude and bandwidth. This is because of that fact that passive seismic acquisition requires greater instrumentation sensitivity, noise immunity, and bandwidth, with active seismic acquisition, where vibratory or impulsive sources were utilized to receive reflections through geophones. Therefore, in the case of passive seismic acquisition, it is necessary to select the best monitoring equipment for its success or failure. Hence, concerning sensors performance, this paper highlights the technological gap and motivates developing dedicated sensors for optimal solution at lower frequencies. Thus, the improved passive seismic recording helps in oil and gas industry to perform better fracture mapping and identify more appropriate stratigraphy at low frequencies.

scholarly journals Comparison of volcanic explosions in Japan using impulsive ionospheric disturbances

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Mokhamad Nur Cahyadi ◽  
Eko Yuli Handoko ◽  
Ririn Wuri Rahayu ◽  
Kosuke Heki
Keyword(s):  
Wave Speed ◽  
Volcanic Eruptions ◽  
Satellite System ◽  
Electron Content ◽  
Total Electron ◽  
F Region ◽  
Gnss Receivers ◽  
Explosive Volcanic Eruptions ◽  
Global Navigation Satellite ◽  
Volcanic Explosions

AbstractUsing the ionospheric total electron content (TEC) data from ground-based Global Navigation Satellite System (GNSS) receivers in Japan, we compared ionospheric responses to five explosive volcanic eruptions 2004–2015 of the Asama, Shin-Moe, Sakurajima, and Kuchinoerabu-jima volcanoes. The TEC records show N-shaped disturbances with a period ~ 80 s propagating outward with the acoustic wave speed in the F region of the ionosphere. The amplitudes of these TEC disturbances are a few percent of the background absolute vertical TEC. We propose to use such relative amplitudes as a new index for the intensity of volcanic explosions. Graphical Abstract

Volcanic Tremor and its Relation to Volcano- and Glacier-related Processes

2021 ◽  
Author(s):  
Eva P. S. Eibl
Keyword(s):  
Early Warning ◽  
Volcanic Tremor ◽  
Volcanic Eruptions ◽  
Seismic Signal ◽  
Magma Flow ◽  
Rotational Seismology ◽  
Multidisciplinary Data ◽  
Single Station ◽  
Glacial Environments ◽  
Remote Sites

&lt;p&gt;Volcanic eruptions can affect the climate system, the environment and society. On ice covered volcanoes this threat intensifies due to the increasing explosivity in contact with water. Monitoring and early-warning of such eruptions is closely linked to real-time, multidisciplinary data analysis. This builds on a good understanding and location of the recorded signals.&lt;/p&gt;&lt;p&gt;I will summarize my work on understanding and modelling volcanic tremor, a long-lasting seismic signal with emergent onset. This tremor accompanies various volcano- and glacier-related processes and has to be reliably detected and distinguished from other sources. My examples range from modelling pre-eruptive subglacial tremor and silent magma flow, to monitoring eruptive tremor, to early warning of subglacial flooding, to hydrothermal explosions and boiling and other sources such as helicopters. These results are based on array analysis, amplitude location techniques and single-station arrays but I will also risk a look into the future embracing the emerging field of rotational seismology which might solve some challenges we face in volcanic and glacial environments and advance our understanding and modelling of volcanic signals at remote sites.&lt;/p&gt;

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