Precursory worldwide signatures of earthquake occurrences on Swarm satellite data

AbstractThe study of the preparation phase of large earthquakes is essential to understand the physical processes involved, and potentially useful also to develop a future reliable short-term warning system. Here we analyse electron density and magnetic field data measured by Swarm three-satellite constellation for 4.7 years, to look for possible in-situ ionospheric precursors of large earthquakes to study the interactions between the lithosphere and the above atmosphere and ionosphere, in what is called the Lithosphere-Atmosphere-Ionosphere Coupling (LAIC). We define these anomalies statistically in the whole space-time interval of interest and use a Worldwide Statistical Correlation (WSC) analysis through a superposed epoch approach to study the possible relation with the earthquakes. We find some clear concentrations of electron density and magnetic anomalies from more than two months to some days before the earthquake occurrences. Such anomaly clustering is, in general, statistically significant with respect to homogeneous random simulations, supporting a LAIC during the preparation phase of earthquakes. By investigating different earthquake magnitude ranges, not only do we confirm the well-known Rikitake empirical law between ionospheric anomaly precursor time and earthquake magnitude, but we also give more reliability to the seismic source origin for many of the identified anomalies.

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Rikitake Law, relating precursor time and earthquake magnitude, confirmed by Swarm satellite data

10.5194/egusphere-egu2020-20281 ◽

2020 ◽

Author(s):

Saioa A. Campuzano ◽

Gianfranco Cianchini ◽

Angelo De Santis ◽

Dedalo Marchetti ◽

Loredana Perrone ◽

...

Keyword(s):

Electron Density ◽

Satellite Data ◽

Time Series Data ◽

Earthquake Magnitude ◽

Series Data ◽

Time Interval ◽

Empirical Law ◽

Preparation Phase ◽

Whole Space ◽

Lithospheric Stress

Rikitake [1987] studied different types of ground earthquake precursors and presented an empirical law (for what he called &#8220;precursors of the 1st kind&#8221;) expressing a linear relationship between the logarithm of the anomaly precursor time and the earthquake magnitude. To look for possible in-situ ionospheric precursors of large (M5.5+) earthquakes, here we analyse a long-term time series data from the three-satellite Swarm constellation, in particular electron density and magnetic field data. We define the anomalies statistically in the whole space-time interval of interest and use a superposed epoch approach to study the possible relation with the earthquakes. We find some clear concentrations of electron density and magnetic anomalies from several months to a few days before the earthquake occurrences. Such anomaly clustering is, in general, statistically significant with respect to homogeneous random simulations, supporting a coupling of the lithosphere with the above atmosphere and ionosphere during the preparation phase of earthquakes. Finally, by investigating different earthquake magnitude ranges, we confirm the Rikitake empirical law between ionospheric anomaly precursor time and earthquake magnitude. Our work represents the first time that this empirical law has been confirmed for satellite data. We also explain this empirical law with a diffusion model of lithospheric stress.

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Magnetic Field and Electron Density Data Analysis from Swarm Satellites Searching for Ionospheric Effects by Great Earthquakes: 12 Case Studies from 2014 to 2016

Atmosphere ◽

10.3390/atmos10070371 ◽

2019 ◽

Vol 10 (7) ◽

pp. 371 ◽

Cited By ~ 7

Author(s):

Angelo De Santis ◽

Dedalo Marchetti ◽

Luca Spogli ◽

Gianfranco Cianchini ◽

F. Javier Pavón-Carrasco ◽

...

Keyword(s):

Magnetic Field ◽

Electron Density ◽

Geomagnetic Latitude ◽

Statistical Correlation ◽

Satellite Mission ◽

Strong Earthquakes ◽

Density Data ◽

Ionospheric Effects ◽

Swarm Satellites ◽

Swarm Satellite

We analyse Swarm satellite magnetic field and electron density data one month before and one month after 12 strong earthquakes that have occurred in the first 2.5 years of Swarm satellite mission lifetime in the Mediterranean region (magnitude M6.1+) or in the rest of the world (M6.7+). The search for anomalies was limited to the area centred at each earthquake epicentre and bounded by a circle that scales with magnitude according to the Dobrovolsky’s radius. We define the magnetic and electron density anomalies statistically in terms of specific thresholds with respect to the same statistical quantity along the whole residual satellite track (|geomagnetic latitude| ≤ 50°, quiet geomagnetic conditions). Once normalized by the analysed satellite tracks, the anomalies associated to all earthquakes resemble a linear dependence with earthquake magnitude, so supporting the statistical correlation with earthquakes and excluding a relationship by chance.

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Real-World Experience with Artificial Intelligence-Based Triage in Transferred Large Vessel Occlusion Stroke Patients

Cerebrovascular Diseases ◽

10.1159/000515320 ◽

2021 ◽

pp. 1-6

Author(s):

Jacob R. Morey ◽

Xiangnan Zhang ◽

Kurt A. Yaeger ◽

Emily Fiano ◽

Naoum Fares Marayati ◽

...

Keyword(s):

Artificial Intelligence ◽

Clinical Outcomes ◽

Warning System ◽

Large Vessel ◽

Time Interval ◽

Large Vessel Occlusion ◽

Time Intervals ◽

Vessel Occlusion ◽

Left Behind ◽

Stroke Center

Background and Purpose: Randomized controlled trials have demonstrated the importance of time to endovascular therapy (EVT) in clinical outcomes in large vessel occlusion (LVO) acute ischemic stroke. Delays to treatment are particularly prevalent when patients require a transfer from hospitals without EVT capability onsite. A computer-aided triage system, Viz LVO, has the potential to streamline workflows. This platform includes an image viewer, a communication system, and an artificial intelligence (AI) algorithm that automatically identifies suspected LVO strokes on CTA imaging and rapidly triggers alerts. We hypothesize that the Viz application will decrease time-to-treatment, leading to improved clinical outcomes. Methods: A retrospective analysis of a prospectively maintained database was assessed for patients who presented to a stroke center currently utilizing Viz LVO and underwent EVT following transfer for LVO stroke between July 2018 and March 2020. Time intervals and clinical outcomes were compared for 55 patients divided into pre- and post-Viz cohorts. Results: The median initial door-to-neuroendovascular team (NT) notification time interval was significantly faster (25.0 min [IQR = 12.0] vs. 40.0 min [IQR = 61.0]; p = 0.01) with less variation (p < 0.05) following Viz LVO implementation. The median initial door-to-skin puncture time interval was 25 min shorter in the post-Viz cohort, although this was not statistically significant (p = 0.15). Conclusions: Preliminary results have shown that Viz LVO implementation is associated with earlier, more consistent NT notification times. This application can serve as an early warning system and a failsafe to ensure that no LVO is left behind.

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Die zeitliche Änderung der radialen Elektronendichteverteilung beim Theta-Pinch

Zeitschrift für Naturforschung A ◽

10.1515/zna-1963-8-903 ◽

1963 ◽

Vol 18 (8-9) ◽

pp. 895-900

Author(s):

Franz Peter Küpper

Keyword(s):

Density Distribution ◽

Electron Density ◽

Electron Density Distribution ◽

Electron Distribution ◽

Radial Symmetry ◽

Zero Order ◽

Time Interval ◽

Interferometric Method ◽

Density Distributions ◽

Theta Pinch

In a θ-pinch the radial symmetry of the electron density distribution as a function of time has been measured by a MACH—ZEHNDER interferometer. In a time interval of 400 nsec during a discharge an image converter made three pictures (exposure times of 10 nsec each) . Up to 100 nsec after the first compression, the experimental results show different density distributions for the cases of trapped parallel and antiparallel magnetic fields. Complete radial symmetry of the electron density distribution was not found.Another interferometric method for measuring the radial symmetry of the electron distribution by observing “zero order” fringes is described.

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Insight on the results of three different correlation analyses between satellite TIR anomalies and earthquake occurrence

10.5194/egusphere-egu21-12298 ◽

2021 ◽

Author(s):

Carolina Filizzola ◽

Roberto Colonna ◽

Alexander Eleftheriou ◽

Nicola Genzano ◽

Katsumi Hattori ◽

...

Keyword(s):

Seismic Hazard ◽

International Workshop ◽

Statistical Correlation ◽

Physical Models ◽

Short Term ◽

Correlation Analyses ◽

Multi Temporal ◽

Casual Relation ◽

Large Earthquakes

In order to evaluate the potentiality of the parameter &#8220;RST-based satellite TIR anomalies&#8221; in relation with earthquake (M&#8805;4) occurrence, in recent years we performed three long-term statistical correlation analyses on different seismically active areas, such as Greece (Eleftheriou et al., 2016), Italy (Genzano et al., 2020), and Japan (Genzano et al., 2021).With this aim, by means of the RST (Robust Satellite Techniques; Tramutoli, 1998, 2007) approach we analysed ten-year time series of satellite images collected by the SEVIRI sensor (on board the MSG platforms) over Greece (2004-2013) and Italy (2004-2014), and by the JAMI and IMAGER sensors (on board the MTSAT satellites) over Japan (2005-2015). &#160;By applying empirical spatial-temporal rules, which are established also taking account of the physical models up to now proposed to explain seismic TIR anomaly appearances, the performed long -term correlation analyses put in relief that a non-casual relation exists between satellite TIR anomalies and the occurrence of earthquakes.At the same time, in the carried out studies we introduced and validated refinements and improvements to the RST approach, which are able to minimize the proliferation of the false positives (i.e. TIR anomalies independent from the seismic sources, but due to other causes such as meteorological factors).&#160; &#160;&#160;Here, we summarize the achieved results and discuss them from the perspective of a multi-parameter system, which could improve our present knowledge on the earthquake-related processes and increase our capacity to assess the seismic hazard in the medium-short term (months to days).&#160;ReferencesEleftheriou, A., C. Filizzola, N. Genzano, T. Lacava, M. Lisi, R. Paciello, N. Pergola, F. Vallianatos, and V. Tramutoli (2016), Long-Term RST Analysis of Anomalous TIR Sequences in Relation with Earthquakes Occurred in Greece in the Period 2004&#8211;2013, Pure Appl. Geophys., 173(1), 285&#8211;303, doi:10.1007/s00024-015-1116-8.Genzano, N., C. Filizzola, M. Lisi, N. Pergola, and V. Tramutoli (2020), Toward the development of a multi parametric system for a short-term assessment of the seismic hazard in Italy, Ann. Geophys, 63, 5, PA550, doi:10.4401/ag-8227.Genzano, N., C. Filizzola, K. Hattori, N. Pergola, and V. Tramutoli (2021), Statistical correlation analysis between thermal infrared anomalies observed from MTSATs and large earthquakes occurred in Japan (2005 - 2015), Journal of Geophysics Research &#8211; Solid Earth, doi: 10.1029/2020JB020108 (accepted).Tramutoli, V. (1998), Robust AVHRR Techniques (RAT) for Environmental Monitoring: theory and applications, in Proceedings of SPIE, vol. 3496, edited by E. Zilioli, pp. 101&#8211;113, doi: 10.1117/12.332714Tramutoli, V. (2007), Robust Satellite Techniques (RST) for Natural and Environmental Hazards Monitoring and Mitigation: Theory and Applications, in 2007 International Workshop on the Analysis of Multi-temporal Remote Sensing Images, pp. 1&#8211;6, IEEE. doi: 10.1109/MULTITEMP.2007.4293057

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Bayesian probabilities for occurrence of large earthquakes in the seismogenic sources of Japan and Phillipine during the period 1998-2017

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.17271 ◽

2001 ◽

Vol 34 (4) ◽

pp. 1619

Author(s):

T. M. TSAPANOS ◽

O. CH. GALANIS ◽

S. D. MAVRIDOU ◽

M. P. HELMl

Keyword(s):

Seismic Hazard ◽

Bayesian Statistics ◽

Poisson Distribution ◽

Bayesian Approach ◽

Seismic Sources ◽

Time Interval ◽

Seismogenic Sources ◽

The One ◽

Large Earthquakes ◽

The Bayesian Approach

The Bayesian statistics is adopted in 11 seismic sources of Japan and 14 of Philippine in order to estimate the probabilities of occurrence of large future earthquakes, assuming that earthquakes occurrence follows the Poisson distribution. The Bayesian approach applied represents the probability that a certain cut-off magnitude (or larger) will exceed in a given time interval of 20 years, that is 1998-2017. This cut-off magnitude is chosen the one with M=7.0 or greater. In this case we can consider these obtained probabilities as a seismic hazard presentation. More over curves are produced which present the fluctuation of the seismic hazard between these seismic sources. These graphs of varying probability are useful either for engineering or other practical purposes

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Tectonic Geomorphology and Paleoseismology of the Sharkhai fault: a new source of seismic hazard for Ulaanbaatar (Mongolia)

10.5194/se-2021-91 ◽

2021 ◽

Author(s):

Abeer Al-Ashkar ◽

Antoine Schlupp ◽

Matthieu Ferry ◽

Ulziibat Munkhuu

Keyword(s):

Seismic Hazard ◽

Scaling Laws ◽

Active Faults ◽

Seismic Hazard Assessment ◽

Capital City ◽

Tectonic Geomorphology ◽

Time Interval ◽

Coseismic Slip ◽

Slip Rates ◽

Large Earthquakes

Abstract. We present new constraints from tectonic geomorphology and paleoseismology along the newly discovered Sharkhai fault near the capital city of Mongolia. Detailed observations from high resolution Pleiades satellite images and field investigations allowed us to map the fault in detail, describe its geometry and segmentation, characterize its kinematics, and document its recent activity and seismic behavior (cumulative displacements and paleoseismicity). The Sharkhai fault displays a surface length of ~40 km with a slightly arcuate geometry, and a strike ranging from N42° E to N72° E. It affects numerous drainages that show left-lateral cumulative displacements reaching 57 m. Paleoseismic investigations document the faulting and deposition record for the last ~3000 yr and reveal that the penultimate earthquake (PE) occurred between 1515 ± 90 BC and 945 ± 110 BC and the most recent event (MRE) occurred after 860 ± 85 AD. The resulting time interval of 2080 ± 470 years is the first constraint on the Sharkhai fault for large earthquakes. On the basis of our mapping of the surface rupture and the resulting segmentation analysis, we propose two possible scenarios for large earthquakes with likely magnitudes between 6.4 ± 0.2 and 7.1 ± 0.2. Furthermore, we apply scaling laws to infer coseismic slip values and derive preliminary estimates of long-term slip rates between 0.2 ± 0.2 and 1.0 ± 0.5 mm/y. Finally, we propose that these original observations and results from a newly discovered fault should be taken into account for the seismic hazard assessment for the city of Ulaanbaatar and help build a comprehensive model of active faults in that region.

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Identification of Precursory Anomalies before Moderate-strong Earthquakes in Junction of Shanxi-Hebei-Inner Mongolia Area

E3S Web of Conferences ◽

10.1051/e3sconf/202020601011 ◽

2020 ◽

Vol 206 ◽

pp. 01011

Author(s):

Li Hong

Keyword(s):

Standard Deviation ◽

Inner Mongolia ◽

Strong Earthquake ◽

Earthquake Magnitude ◽

Parameter Analysis ◽

Time Interval ◽

Study Region ◽

Strong Earthquakes ◽

Spectrum Method ◽

Prediction Efficiency

In this paper, we take the Junction of Shanxi-Hebei-Inner Mongolia area as study region using earthquake corresponding relevancy spectrum method (ECRS method) to identify comprehensive precursory anomalies before moderate-strong earthquake. On base of single-parameter relevancy spectrum database with target earthquake magnitude as Ms4.7 and initial earthquake magnitude as Ms1, we carry on multi-parameter analysis and find that result with time interval of 9 months and anomaly threshold with 0.40 times standard deviation has better prediction efficiency. Its anomaly corresponding rate and earthquake corresponding rate are 6/10 and 9/9 respectively.

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Back Analysis of Short-Term Seismic Hazard Indicators of Larger Seismic Events in Deep Underground Mines (LKAB, Kiirunavaara Mine, Sweden)

Pure and Applied Geophysics ◽

10.1007/s00024-019-02352-8 ◽

2019 ◽

Vol 177 (2) ◽

pp. 763-785

Author(s):

Emilia Nordström ◽

Savka Dineva ◽

Erling Nordlund

Keyword(s):

Seismic Hazard ◽

Early Warning ◽

Back Analysis ◽

Warning System ◽

Source Area ◽

Seismic Source ◽

Underground Mines ◽

Seismic Events ◽

Short Term ◽

Deep Underground

Abstract Back analysis for evaluation of the merits of the short-term seismic hazard indicators (precursors) used in the mines and their potential application for early warning was carried out for fourteen seismic events that potentially caused damage in Kiirunavaara Mine, Sweden, selected according to our designed criteria. Five short-term hazard indicators: Seismic Activity Rate (SAR), Cumulative Seismic Moment (CSM), Energy Index (EI), Cumulative Apparent Volume (CAV) and Seismic Apparent Stress Frequency (ASF) were tested. The behaviour of the indicators was studied using the parameters of all seismic events within a sphere around the hypocenter location of the analyzed seismic source within one month before the main (damaging) event. The size of the sphere equals the estimated radius of the analyzed seismic source (area of inelastic deformation). mXrap software (Australian Centre for Geomechanics) was used for data visualization, manipulation, analysis and extraction. The results from the main analysis showed a good agreement between the expected and actual behaviour of the SAR, CSM and CAV indicators. In overall, CSM and CAV ranked the highest positive/expected behaviour followed by SAR (Table 3). The EI and ASF ranked lowest and showed to be sensitive to the number of events within the source sphere. The rate of false warnings and missed warnings was also investigated for the 25 days-long period before the damaging events. A similar trend was observed as for the main analysed event. The results from this study can be used for further improvement of the short-term hazard estimations and early warning system in deep underground mines.

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Ionospheric variations before some large earthquakes over Sumatra

Natural Hazards and Earth System Science ◽

10.5194/nhess-11-597-2011 ◽

2011 ◽

Vol 11 (2) ◽

pp. 597-611 ◽

Cited By ~ 30

Author(s):

A. M. Hasbi ◽

M. A. Mohd Ali ◽

N. Misran

Keyword(s):

Electron Density ◽

Earthquake Epicenter ◽

Equatorial Anomaly ◽

Density Data ◽

Density Measurements ◽

Champ Satellite ◽

Density Analysis ◽

Large Earthquakes ◽

Electron Density Analysis ◽

Champ Data

Abstract. The paper investigates the ionospheric variations before some large earthquakes that occurred during 2004–2007 in Sumatra using GPS and CHAMP data. The TEC shows the occurrence of positive and negative anomalies detected within a few hours to 6 days before the earthquakes. These anomalies mostly occur during the daytime hours between 4 and 17 LT. The TEC anomalies are mostly consistent with the CHAMP satellite electron density data. The electron density analysis over the 28 March 2005 earthquake epicenter shows that an equatorial anomaly modification took place a few days before the event. The modification took shape in the form of crest amplification during the daytime. The comparison between the TEC and electron density measurements during very quiet geomagnetic conditions is shown to be a useful indicator of a forthcoming earthquake.

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