scholarly journals Can Repetitive Small Magnitude-Induced Seismic Events Actually Cause Damage?

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Oliver-Denzil S. Taylor ◽  
Alanna P. Lester ◽  
Theodore A. Lee ◽  
Mihan H. McKenna
Keyword(s):  
Potential Risk ◽  
Critical Infrastructure ◽  
Gas Production ◽  
Seismic Events ◽  
Geothermal Systems ◽  
Small Magnitude ◽  
Time Period ◽  
Reservoir Impoundment ◽  
Definitive Statement ◽  
Mining Wastewater

Geoengineering activities such as reservoir impoundment, mining, wastewater injection, geothermal systems, and CO2 capture have been linked directly to induced seismicity. With the industrial boom in natural shale gas production regions previously aseismic areas have seen an exponential growth in the frequency of small magnitude events, with multiple events observed in close proximity within a 24-hour time period. While the overwhelming majority of induced seismic research has focused on the causality, the potential risk posed to critical federal infrastructure has escaped scrutiny. This proposes the question, “Can repetitive small magnitude-induced seismic events actually cause damage?” A review of the potential risk is presented herein, concluding that a simplistic definitive statement of whether single or multiple small magnitude-induced seismic events do or do not cause damage to critical infrastructure cannot be justified, and warrants additional study. However, recent observations and research suggest the likelihood that these geoengineering-induced events can and do cause detrimental degradation of the subsurface (damaging the overlying structure) is not insignificant.

scholarly journals How to deliver information on induced seismicity to the authorities and general public? 

2021 ◽  
Author(s):  
Niina Junno ◽  
Pia Bäcklund ◽  
Johanna Tuomisaari ◽  
Kati Oinonen ◽  
Toni Veikkolainen ◽  
...  
Keyword(s):  
Social Media ◽  
Free Energy ◽  
Seismic Risk ◽  
Power Plants ◽  
Risk Mitigation ◽  
Seismic Events ◽  
Geothermal Systems ◽  
Small Magnitude ◽  
The Public ◽  
Potential Risks

<p>Alternative, carbon-free energy sources are essential to regulate the global climate crisis. Geothermal energy – i.e., heat harvested by geothermal systems by drilling geothermal wells to circulate water in a fractured hot rock mass at the depth of 1-7 km – has a huge potential as an environmentally friendly carbon-free energy source. One of the drawbacks is that geothermal systems can induce small-magnitude earthquakes that pose seismic risk to critical sensitive infrastructure. SEISMIC RISK - Mitigation of induced seismic risk in urban environments -project focuses on how to evaluate, mitigate and communicate seismic hazard and risk in an urban environment. Some of the associated challenges are the unclear regulatory, administrative and policy processes and unclear roles of the different actors. Another problem concerns defining what constitutes relevant information and how it should be disseminated to the public.</p><p>One part of the project is to carry out interviews of stakeholders (energy companies, municipalities and state authorities) on, how they perceive the current situation. These will give information on 1) the extent to which different actors have a common understanding of the situation and potential risks, 2) who should be responsible for coordinating risk management, and 3) how citizens should be informed of potential risks and should they be able to participate in location decisions of such geothermal power plants. Another part of the project is focusing on, how social media can better be used for rapid communication of induced seismic events and for the gathering of observations. Currently social media (Twitter) is already used for rapid notification of seismic events to the public. Gathering of macroseismic observations is handled online.</p>

Infant fatality patterns in shared sleep: keys to intervention strategies?

2021 ◽  
Vol 65 (1) ◽  
pp. 1322-1326
Author(s):  
Dorothy Ann Drago ◽  
Carol Pollack-Nelson ◽  
Sarah Beth Newens
Keyword(s):  
Cause Of Death ◽  
Potential Risk ◽  
Intervention Strategies ◽  
Consumer Product Safety Commission ◽  
Time Period ◽  
Reduction Strategies ◽  
Sleep Environment ◽  
Risk Reduction Strategies ◽  
The U.S ◽  
Age And Sex

This study examines infant fatalities that occurred while sharing a sleep surface. Fatality data reported to the U.S. Consumer Product Safety Commission (CPSC) during the time period January, 2013 through December, 2017 and involving infants through age 10 months were reviewed. 1,587 Cases were analyzed on the following variables: infant age and sex; sleep environment by product; cause of death; fatality pattern; and breastfeeding, where it was mentioned. 97% Of deaths were due to some form of asphyxia. Adult beds were associated with 78% of shared sleep fatalities, and the primary fatality pattern was overlay (35.4%)/probable overlay (8.8%). Infants <3 months made up 65% of fatalities. The data reflect that bedsharing continues, despite AAP guidelines to the contrary, and that overlay is the primary hazard pattern to be addressed. This paper discusses potential risk reduction strategies that may reduce the potential for overlay fatalities.

A Frequency-Domain-Based Algorithm for Detecting Microseismicity Using Dense Surface Seismic Arrays

2021 ◽  
Author(s):  
Maria Mesimeri ◽  
Kristine L. Pankow ◽  
James Rutledge
Keyword(s):  
Frequency Domain ◽  
Detection Method ◽  
Maximum Amplitude ◽  
High Energy ◽  
Aftershock Sequence ◽  
Anthropogenic Activity ◽  
Small Scale ◽  
Seismic Events ◽  
Small Magnitude ◽  
Seismic Arrays

ABSTRACT We propose a new frequency-domain-based algorithm for detecting small-magnitude seismic events using dense surface seismic arrays. Our proposed method takes advantage of the high energy carried by S waves, and approximate known source locations, which are used to rotate the horizontal components to obtain the maximum amplitude. By surrounding the known source area with surface geophones, we achieve a favorable geometry for locating the detected seismic events with the backprojection method. To test our new detection method, we used a dense circular array, consisting of 151 5 Hz three-component geophones, over a 5 km aperture that was in operation at the Utah Frontier Observatory for Research in Geothermal Energy (FORGE) in southcentral Utah. We apply the new detection method during a small-scale test injection phase at FORGE, and during an aftershock sequence of an Mw 4.1 earthquake located ∼30  km north of the geophone array, within the Black Rock volcanic field. We are able to detect and locate microseismic events (Mw&lt;0) during injections, despite the high level of anthropogenic activity, and several aftershocks that are missing from the regional catalog. By comparing our method with known algorithms that operate both in the time and frequency domain, we show that our proposed method performs better in the case of the FORGE injection monitoring, and equally well for the off-array aftershock sequence. Our new method has the potential to improve microseismic event detections even in extremely noisy environments, and the proposed location scheme serves as a direct discriminant between true and false detections.

scholarly journals Nonlinear multidimensional scaling and visualization of earthquake clusters over space, time and feature space

2005 ◽  
Vol 12 (1) ◽  
pp. 117-128 ◽  
Author(s):  
W. Dzwinel ◽  
D. A. Yuen ◽  
K. Boryczko ◽  
Y. Ben-Zion ◽  
S. Yoshioka ◽  
...  
Keyword(s):  
Clustering Algorithm ◽  
Synthetic Data ◽  
Feature Space ◽  
Seismic Events ◽  
Agglomerative Clustering ◽  
Local Cluster ◽  
Small Magnitude ◽  
Earthquake Parameters ◽  
Dimensional Scaling ◽  
Multi Dimensional Scaling

Abstract. We present a novel technique based on a multi-resolutional clustering and nonlinear multi-dimensional scaling of earthquake patterns to investigate observed and synthetic seismic catalogs. The observed data represent seismic activities around the Japanese islands during 1997-2003. The synthetic data were generated by numerical simulations for various cases of a heterogeneous fault governed by 3-D elastic dislocation and power-law creep. At the highest resolution, we analyze the local cluster structures in the data space of seismic events for the two types of catalogs by using an agglomerative clustering algorithm. We demonstrate that small magnitude events produce local spatio-temporal patches delineating neighboring large events. Seismic events, quantized in space and time, generate the multi-dimensional feature space characterized by the earthquake parameters. Using a non-hierarchical clustering algorithm and nonlinear multi-dimensional scaling, we explore the multitudinous earthquakes by real-time 3-D visualization and inspection of the multivariate clusters. At the spatial resolutions characteristic of the earthquake parameters, all of the ongoing seismicity both before and after the largest events accumulates to a global structure consisting of a few separate clusters in the feature space. We show that by combining the results of clustering in both low and high resolution spaces, we can recognize precursory events more precisely and unravel vital information that cannot be discerned at a single resolution.

scholarly journals Evidence of preliminary prognosis of appearance of catastrophic earthquake and strong tsunami in the region of Tarapacá, Chile

2019 ◽  
Author(s):  
Raissa K. Mazova ◽  
Jorge F. Van Den Bosch ◽  
Natalia A. Baranova ◽  
Gustavo A. Oses
Keyword(s):  
Historical Earthquakes ◽  
Seismic Events ◽  
Tsunami Waves ◽  
Work Support ◽  
Chilean Coast ◽  
Catastrophic Earthquake ◽  
Time Period

Abstract. Are analyzed the catastrophic seismic events near Chilean coast and generated by them tsunami 1 April 2014 to north of Iquique with magnitude 8.2. It is noted that event occurred 1 April 2014 was in fact predicted in work (Mazova and Ramirez 1999), in which there were analyzed all strongest Chilean tsunamigenic earthquakes with sources near the Chilean coast. Analysis of catastrophic earthquakes and tsunamis in given region, localization of source of historical earthquakes and character of generated by them tsunami waves permitted authors in that time to make a conclusion about possibility of repeated catastrophic earthquake and tsunami in near 10–20 years. The events near Iquique and Arica city in April 2014 are in this time period. Thus, the evidences, presented in this work, support preliminary prognosis made by authors in 1999.

scholarly journals The damaging character of shallow 20th century earthquakes in the Hainaut coal area (Belgium)

2021 ◽  
Author(s):  
Thierry Camelbeeck ◽  
Koen Van Noten ◽  
Thomas Lecocq ◽  
Marc Hendrickx
Keyword(s):  
Ground Motion ◽  
20Th Century ◽  
Focal Depth ◽  
Seismic Events ◽  
Late 20Th Century ◽  
Small Magnitude ◽  
Close Link ◽  
Epicentral Intensity ◽  
The 19Th Century ◽  
The Impact

Abstract. Shallow, light to moderate magnitude earthquakes in stable continental regions can have a damaging impact on vulnerable surface constructions. In the coal area of the Hainaut province in Belgium, a century of shallow seismic activity occurred from the end of the 19th century until the late 20th century. This seismicity is the second largest source of seismic hazard in northwestern Europe, after the Lower Rhine Embayment. The present study synthesises the impact and damage caused by this unique shallow seismicity. Reviewing intensity data provided in official macroseismic surveys held by the Royal Observatory of Belgium, press reports, and contemporary scientific studies resulted in a complete macroseismic intensity dataset. The strong shaking of five seismic events with moment magnitudes Mw around 4.0, which occurred on 3 June 1911, 3 April 1949, 15 December 1965, 16 January 1966, and 28 March 1967, locally caused widespread moderate damage to buildings corresponding to maximum intensity VII in the EMS-98 scale. For 28 earthquakes, detailed macroseismic maps were created. Our study highlights the capability of shallow, small-magnitude earthquakes to generate damage. Subsequently, using the Hainaut intensity dataset, we modelled a new Hainaut intensity attenuation law and created relationships linking magnitude, epicentral intensity and focal depth. Using these relationships, we estimated the location and magnitude of pre-1985 earthquakes that occurred prior to deployment of the modern digital Belgian seismic network. Estimated focal depths allowed discriminating between two different types of earthquakes. Some events were very shallow, only a few hundred metres deep, suggesting a close link to mining activities. Other earthquakes, including the largest and most damaging events, occurred at depths greater than 2 km but no deeper than 6 km, which would exclude a direct relationship with mining, but yet still might imply a triggering causality. This work results in a new updated earthquake catalogue including 123 seismic events. Our attenuation modelling moreover suggests that current hazard maps overestimated ground motion levels in the Hainaut area due to the use of inadequate ground motion prediction equations. Our Hainaut attenuation model is hence useful to evaluate the potential impact of current and future, e.g. geothermal energy, projects in the Hainaut area and other regions with a similar geological configuration.

Simultaneous microseismic event localization and source mechanism determination

Geophysics ◽  
2015 ◽  
Vol 80 (1) ◽  
pp. KS1-KS9 ◽  
Author(s):  
Oksana Zhebel ◽  
Leo Eisner
Keyword(s):  
Oil And Gas ◽  
Signal To Noise Ratio ◽  
Moment Tensor ◽  
Microseismic Monitoring ◽  
Primary Objective ◽  
Gas Production ◽  
Source Mechanism ◽  
Seismic Events ◽  
Near Surface ◽  
Microseismic Event

Microseismic monitoring has become a tool of choice for the development and optimization of oil and gas production from unconventional reservoirs. The primary objective of (micro) seismic monitoring includes localization of (micro) seismic events and characterization of their source mechanisms. Most seismic events are of a nonexplosive nature, and thus, there are waveform (polarity) differences among receivers. Specifically, double-couple sources represented a challenge for migration-based localization techniques. We developed and applied a new migration-type location technique combined with source mechanism inversion that allowed for constructive interference of signal in seismic waveforms. The procedure included constructing image functions by stacking the amplitudes with compensated polarity changes. The compensation weights were calculated by using moment tensor inversion. This method did not require any picking of arrivals at individual receivers, but it required receivers to be distributed in multiple azimuths and offsets. This made the technique suitable for surface or near-surface monitoring, in which a low signal-to-noise ratio (S/N) can be overcome by stacking. Furthermore, the advantage of this technique was that in addition to the position in time and space, we also determined the source mechanism. We determined with numerical tests that the proposed technique can be used for detection and location of events with S/Ns as low as 0.05 at individual (prestacked) receivers. Furthermore, we found that other source mechanism parameters such as magnitude, volumetric, or shear components of the source mechanism were not suitable for the location. Finally, we applied the proposed technique to a microseismic event of moment magnitude [Formula: see text] induced during the hydraulic fracturing treatment of a gas shale reservoir in North America.

Focal mechanisms for small to intermediate earthquakes in the northern part of the Alps and their seismotectonic interpretation

2020 ◽  
Author(s):  
Thomas Plenefisch ◽  
Laura Barth ◽  
Keyword(s):  
Stress Field ◽  
Focal Mechanisms ◽  
Small Magnitude ◽  
Moment Tensors ◽  
Time Period ◽  
Double Couple ◽  
Geodynamic Processes ◽  
The Alps ◽  
Seismic Networks ◽  
Seismotectonic Interpretation

&lt;p&gt;In the framework of the AlpArray project more than 600 broadband stations have been installed and operated in the Alps and the surroundings. Together with the permanent stations in the area it is one of the most densely spaced seismic networks worldwide. Thereby, it offers an excellent opportunity to investigate the seismicity and seismotectonics of the Alpine chain. Due to the huge number of stations focal mechanisms can be calculated even for small magnitude earthquakes with high accuracy. The focal mechanisms are one important key to reveal the contemporary stress field and thus contribute to a better understanding of the geodynamic processes of the Alps.&lt;/p&gt;&lt;p&gt;In our study we focus on small to intermediate earthquakes in the Northern Alps, namely on four distinct sub-regions. These are from West to East the Lake Constance, the Arlberg region, the area of Garmisch-Partenkirchen and the broader region of Innsbruck. In order to calculate the focal mechanisms, we apply the FOCMEC program (Snoke, 2003), which inverts for a pure double-couple source. P-polarities as well as amplitude ratios of SH to P are used as input parameters for the inversion. Thanks to the dense network a good coverage of the focal sphere is achieved in most cases.&lt;/p&gt;&lt;p&gt;Altogether, we calculated focal mechanisms for 25 earthquakes in the magnitude range between 2.5 and 3.5 from the time period 2016 to 2019. Most of the focal mechanisms represent reverse or strike-slip faulting, normal faulting events are rather rare. The mechanisms are analysed with respect to lateral changes along the Northern Alpine. On one hand we compare the mechanisms with mechanisms of older studies as well as with moment tensors of events of slightly larger magnitudes. Those events are the scope of another subproject in the framework of the AlpArray (Petersen et al., 2019). On the other hand, we compare our mechanisms with geological indicators, namely orientation of faults. Finally, the focal mechanisms are used as input to invert for the stress field.&lt;/p&gt;

scholarly journals Application of monitoring guidelines to induced seismicity in Italy

2020 ◽  
Vol 24 (5) ◽  
pp. 1015-1028 ◽  
Author(s):  
Thomas Braun ◽  
Stefania Danesi ◽  
Andrea Morelli
Keyword(s):  
Oil And Gas ◽  
Ground Deformation ◽  
Gas Storage ◽  
Gas Production ◽  
Geothermal Systems ◽  
Traffic Light ◽  
Pilot Studies ◽  
Ground Shaking ◽  
Stress Changes ◽  
Joint Monitoring

AbstractPublic concern about anthropogenic seismicity in Italy first arose in the aftermath of the deadly M ≈ 6 earthquakes that hit the Emilia-Romagna region (northern Italy) in May 2012. As these events occurred in a (tectonically active) region of oil and gas production and storage, the question was raised, whether stress perturbations due to underground industrial activities could have induced or triggered the shocks. Following expert recommendations, in 2014, the Italian Oil & Gas Safety Authority (DGS-UNMIG, Ministry of Economic Development) published guidelines (ILG - Indirizzi e linee guida per il monitoraggio della sismicità, delle deformazioni del suolo e delle pressioni di poro nell’ambito delle attività antropiche), describing regulations regarding hydrocarbon extraction, waste-water injection and gas storage that could also be adapted to other technologies, such as dams, geothermal systems, CO2 storage, and mining. The ILG describe the framework for the different actors involved in monitoring activities, their relationship and responsibilities, the procedure to be followed in case of variations of monitored parameters, the need for in-depth scientific analyses, the definition of different alert levels, their meaning and the parameters to be used to activate such alerts. Four alert levels are defined, the transition among which follows a decision to be taken jointly by relevant authorities and industrial operator on the basis of evaluation of several monitored parameters (micro-seismicity, ground deformation, pore pressure) carried on by a scientific-technical agency. Only in the case of liquid reinjection, the alert levels are automatically activated on the basis of exceedance of thresholds for earthquake magnitude and ground shaking – in what is generally known as a Traffic Light System (TLS). Istituto Nazionale di Geofisica e Vulcanologia has been charged by the Italian oil and gas safety authority (DGS-UNMIG) to apply the ILG in three test cases (two oil extraction and one gas storage plants). The ILG indeed represent a very important and positive innovation, as they constitute official guidelines to coherently regulate monitoring activity on a national scale. While pilot studies are still mostly under way, we may point out merits of the whole framework, and a few possible critical issues, requiring special care in the implementation. Attention areas of adjacent reservoirs, possibly licenced to different operators, may overlap, hence making the point for joint monitoring, also in view of the possible interaction between stress changes related to the different reservoirs. The prescribed initial blank-level monitoring stage, aimed at assessing background seismicity, may lose significance in case of nearby active production. Magnitude – a critical parameter used to define a possible step-up in activation levels – has inherent uncertainty and can be evaluated using different scales. A final comment considers the fact that relevance of TLS, most frequently used in hydraulic fracturing operations, may not be high in case of triggered tectonic events.

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