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(searched for: Atmospheric Pressure Anomalies over Earthquakes Epicenters)
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Eladio Zárate Hernández, Mario Fernández Arce
European Journal of Environment and Earth Sciences, Volume 2, pp 21-25; doi:10.24018/ejgeo.2021.2.4.150

Abstract:
This article is an analysis of the anomalies in atmospheric pressure days before and during the occurrence of earthquakes. The research started from the review of scientific articles in which it has been proposed that atmospheric events generate or trigger seismicity, and that earthquakes alter the atmosphere. Therefore, the atmospheric pressure pattern in Costa Rica during earthquakes with a magnitude greater than or equal to 6.5 Mw, for the period 1950 – 2020, was studied in order to investigate a possible link between atmospheric events and underground processes of the planet. For this, atmospheric pressure anomaly maps were drawn in which the epicenter of the earthquakes was located. Among the results, it stands out that 64% of the epicenters occurred in areas where the pressure anomaly had a value close to or equal to zero. This could indicate, as other authors have suggested, that atmospheric pressure alters the cortical stress pattern, thus contributing to the triggering of earthquakes.
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, Volume 14, pp 5300-5310; doi:10.1109/jstars.2021.3080843

Abstract:
The Index of Ozone Anomaly (IOA) has been proposed to detect changes in tropospheric ozone associated with strong earthquakes. The tropospheric ozone prior and after the 2008 Wenchuan earthquake has been analyzed using IOA. AIRS ozone volume mixing ratio (O3 VMR) at different pressure levels (600, 500, 400, 300, 200 hPa) for an 18-year period 2003-2020 has been considered to identify the unique behavior associated with the strong earthquakes. Our results show distinct increased tropospheric ozone occurred on 5-day (7 May 2008) prior to the main event and distributed along the Longmenshan fault zone. An enhancement in IOA has also been observed around the time of the 2013 Lushan and 2017 Jiuzhaigou earthquakes, but with the different emergence time, which indicates that the unusual behavior of tropospheric ozone depends on the tectonic and geological environment, focal mechanism, focal depth, weather conditions and so on. The location of increased tropospheric ozone indicates the epicenter of earthquakes. The magnitude of earthquake could be one of the important factors affecting the appearance of the anomalous tropospheric ozone. The possible mechanism for the increased tropospheric ozone associated with strong earthquakes was discussed in the present paper. The quasi-synchronous changes of tropospheric ozone and other parameters in the lithosphere/ atmosphere/ ionosphere have been found by combining with the other published results related to the Wenchuan earthquake, which show the existence of coupling during the earthquake preparation phase as suggested by the model of LithosphereAtmosphereIonosphere coupling (LAIC).
Tetiana Skorokhod, Nimrod Inbar,
Published: 4 March 2021
Abstract:
<p>Despite the existence of a large number of observational data and physical models describing the preparation, performance and consequences of Earthquakes (EQ) events, scientists still do not know much about this physical phenomena. A vast amount of efforts and financial means have already been invested in searching for possible precursors of geodynamic and EQ events, which might be considered disproportionate to the progress already achieved. Nevertheless, this important task deserves further investigation, as any encouraging obtained result will pay off all efforts.</p><p>Here, we propose to investigate a multi-parametric integrated approach, augmented by observation from a wide set of possible/potential EQ manifestations in the Lithosphere, Troposphere and Ionosphere. To better tackle the problem of possible EQ precursor detection, four EQ events with magnitudes of 3.9&#8211;4.4 M, which occurred in Lake Kinneret pull-apart basin, Israel from the period of May 1 to September 30, 2018, were examined. The multi-parametric observation were simultaneously collected from several stations within a 100 km radius from the studied EQ epicenters. Thus, the following parameters which were investigated are: gamma-ray emissions both from the subsurface and atmosphere, precipitation, atmospheric temperature and pressure, groundwater level and electrical conductivity measured in two wells, precipitable water vapor (PWV) in the atmosphere extracted from GNSS tropospheric path delays, Total Electron Content (TEC) in the ionosphere extracted from GNSS ionospheric path delays. In addition, geomagnetic and solar parameters such as A- and Kp-indices, 10.7 cm radio flux and sun spot number (SSN), were used to exclude the influence of solar-terrestrial coupling and mitigate false positive signatures.</p><p>Preliminary results indicate anomalous signals (exceeding 2&#963;) at all stations for most of the measured parameters, approximately one month before the studied EQ events. Five significant anomalies, lasting 4-7 days, observed in sub-surface gamma-ray emissions were chosen as reference main precursors. Two of those anomalies (35&#177;2 days and 26&#177;2 days before the EQ events) were accompanied by signal enhancements, measured at other stations located several tens of kilometers apart, in PWV, TEC, groundwater electrical conductivity, Rn and CO2. Another two sub-surface gamma-ray anomalies were correlated with precipitation events, while the last observed anomaly (11&#177;3 days before the EQ events), which is the weakest among the five, was not accompanied by any enhanced measured parameter. According to these results, the multi-parametric approach seems to provide a powerful analysis tool used to differentiate between signals originated from geodynamic and other sources. It is suggested that future research can benefit tremendously from vast multi-parametric continuous data collection and analysis.</p>
, Takanori Kagoshima, Naoto Takahata, Kotaro Shirai, Jin-Oh Park, Glen T. Snyder, Tomo Shibata, Junji Yamamoto, Yoshiro Nishio, Ai-Ti Chen, et al.
Published: 10 December 2020
Frontiers in Earth Science, Volume 8; doi:10.3389/feart.2020.611010

Abstract:
Carbon capture and storage (CCS) is considered a key technology for reducing CO2 emissions into the atmosphere. Nonetheless, there are concerns that if injected CO2 migrates in the crust, it may trigger slip of pre-existing faults. In order to test if this is the case, covariations of carbon, hydrogen, and oxygen isotopes of groundwater measured from Uenae well, southern Hokkaido, Japan are reported. This well is located 13 km away from the injection point of the Tomakomai CCS project and 21 km from the epicenter of September 6th, 2018 Hokkaido Eastern Iburi earthquake (M 6.7). Carbon isotope composition was constant from June 2015 to February 2018, and decreased significantly from April 2018 to November 2019, while total dissolved inorganic carbon (TDIC) content showed a corresponding increase. A decrease in radiocarbon and δ13C values suggests aquifer contamination by anthropogenic carbon, which could possibly be attributable to CCS-injected CO2. If such is the case, the CO2 enriched fluid may have initially migrated through permeable channels, blocking the fluid flow from the source region, increasing pore pressure in the focal region and triggering the natural earthquake where the brittle crust is already critically stressed.
C. Prasanna Simha, Venkatanathan Natarajan, Katlamudi Madhusudhana Rao
Published: 1 September 2020
Geomagnetism and Aeronomy, Volume 60, pp 644-660; doi:10.1134/s0016793220050151

Abstract:
Satellite measurements are becoming popular among the scientific community to identify earthquake precursors since its spatial coverage is more and round the clock measurements are possible. In this paper, we analyzed Total Electron Content (TEC), Outgoing Longwave Radiation (OLR), Sea Level Pressure (SLP), Surface Latent Heat flux (SLHF) and Sea Surface Temperature(SST) to identify any abnormal anomalies before Taiwan earthquakes which occurred on 4th February 2018 (M = 6.1, depth = 12 km) and 6th February 2018 (M = 6.4, depth = 17 km). The GPS data of International GNSS Service(IGS) stations (TWTF and CKSV) which operated 90 and 200 km away from the epicenter of the earthquake on 6th February 2018 respectively, were used for calculation of VTEC. The locations of these stations are within the preparatory zone of these earthquakes. The global parameters such as Dst, Kp, and IMF are also analyzed for the corresponding period of VTEC. We noticed the raise of temporal variations of 5–8 TECU before few days of the present earthquakes. The VTEC and other parameters such as SLP, SST, SLHF, and OLR were analyzed using the “Sliding Interquartile range method” during the period of 09th Jan to 10th Feb 2018 (33 days) to identify the abnormal signal due to these earthquakes. Strong positive anomalies occurred one day before the earthquake of 4th February and 1st, 3rd and 5th day before the Taiwan earthquake of 6th February 2018 with strong anomalous nature with an absolute amplitude of 5–8 TECU.The Cross wavelet analysis between Kp and TEC is carried out to study the impact of global geomagnetic activity on TEC during the seismic event and we found a negligible influence of global geomagnetic activity. The good raise of SLP on the day of the earthquake on 6th February 2018 have been noticed with the raise of 300 mb, the SLHF anomalies are observed at the interface of the earth’s surface and atmosphere. Moreover, anomalous variations in air temperature and OLR were observed 2 days before the occurrence of the earthquake on 6th February 2018. Well co-ordinated scrutiny of various parameters such as TEC, SLHF, and OLR indicates that they can be used as promising precursors to the impending devastating earthquakes with reasonable accuracy.
Saqib Mehdi, Daboor Sultana, Munawar Shah
2019 Sixth International Conference on Aerospace Science and Engineering (ICASE) pp 1-4; doi:10.1109/icase48783.2019.9059131

Abstract:
The monitoring of atmospheric anomalies from ground and space instruments may provide some insights about the precursory nature of future earthquake (EQ). In this paper, multiple atmospheric parameters are analyzed from Remote Sensing Instruments over epicenter of $\mathrm{Mw}=9.1$ (April 11, 2011), Japan within the seismic breeding zone. The long-term temporal data of Nitrogen Dioxide, Sulphur Dioxide (SO2), Aerosol Optical Depth is considered for 4 years before and 4 years after the main shock day. These atmospheric measurements from remote sensing sources showed abnormal values within 10–12 days before the EQ. Similarly, the tropospheric parameters like Aerosol Optical Depth, Nitrogen Dioxide(NO2), SO2 are analyzed and they showed prominent precursors subsequently after the main shock of the EQ. Furthermore, Geo-Potential Height, Surface Air Pressure, Relative Humidity and Temperature changes are also analyzed for two week before main shock. All these precursors may validate the lithosphere-atmospheric coupling within the seismogenic zone for the future EQ.
Published: 13 April 2019
by MDPI
Remote Sensing, Volume 11; doi:10.3390/rs11080901

Abstract:
Big earthquakes often excite the acoustic resonance between the earth’s surface and the lower atmosphere. The perturbations can propagate upward into the ionosphere and trigger ionospheric anomalies detected by dual-frequency GPS observations, but coseismic ionospheric disturbance (CID) directivity and mechanism are not clear. In this paper, the ionospheric response to the Mw = 7.9 Alaska earthquake on 23 January 2018 is investigated from about 100 continuous GPS stations near the epicenter. The fourth-order zero-phase Butterworth band-pass filter with cutoffs of 2.2 mHz and 8 mHz is applied to obtain the ionospheric disturbances. Results show that the CIDs with an amplitude of up to 0.06 total electron content units (TECU) are detected about 10 min after the Alaska earthquake. The CIDs are as a result of the upward propagation acoustic waves triggered by the Rayleigh wave. The propagation velocities of TEC disturbances are around 2.6 km/s, which agree well with the wave propagation speed of 2.7 km/s detected by the bottom pressure records. Furthermore, the ionospheric disturbances following the 2018 Mw = 7.9 Alaska earthquake are inhomogeneous and directional which is rarely discussed. The magnitude of ionospheric disturbances in the western part of the epicenter is more obvious than in the eastern part. This phenomenon also corresponds to the data obtained from the seismographs and bottom pressure records (BPRs) at the eastern and western side of the epicenter.
International Journal of Environmental Science and Technology, Volume 12, pp 1705-1718; doi:10.1007/s13762-014-0731-8

Abstract:
Blocking as an interruption of the climatological storm tracks means an extreme disturbance in the synoptic scale of atmospheric circulation. In this study, we aimed to describe the main role of atmospheric blocking on the earthquake prediction in the southern Iran. We gathered the subjective evidences of a block generation during April 5–9, 2013, which was clearly identified by anomalous data of geopotential height, air temperature, vertical velocity, rainfall rate and latent heat flux. Analysis of geopotential heights at the 500 and 300 hPa levels revealed that there was a dipole split-flow block with associated of a remarkable low-pressure anomaly (−76 m), which has established over southern Iran during April 5–9, 2013. This low pressure into three temporal sequences has influenced three epicenters of upcoming earthquake swarms in south parts of Iran during April and May 2013. Hence, we detected an atmospheric–lithospheric cycle as a climatic conceptual model that describes the chain of the blocking-associated rainfall, preceding rainfall-triggered seismic stress, cyclogenesis, thunderstorm and subsequent stress-induced seismicity. We claimed that the blocking-associated anomalies together with the persistence of low pressure could be the earthquake precursors within 3–33 days before the main seismic shocks in Iran.
Germán D. Padilla, , Nemesio M. Pérez, , , , , , , David Calvo, et al.
Published: 18 December 2013
Pure and Applied Geophysics, Volume 171, pp 1791-1804; doi:10.1007/s00024-013-0756-9

Abstract:
Anomalous changes in the diffuse emission of carbon dioxide within the Masaya caldera have been observed before two seismic events that occurred at 10 and 30 km from the observation site. Their epicenters are located, respectively, south of Managua in Las Colinas (4.3 magnitude) and the Xiloa caldera (3.6 magnitude), in 2002 and 2003, recorded by the geochemical station located at El Comalito, Masaya volcano (Nicaragua). Anomalous increases were observed, which occurred around 50 and 8 days before the main seismic event that took place in Las Colinas, and 4 days before the seismic swarm at the Xiloa caldera, with a maximum CO2 efflux of 9.3 and 10.7 kg m−2 day−1, respectively. The anomalous CO2 efflux increases remained after filtering with multiple regression analysis was applied to the CO2 efflux time series, which indicated that atmospheric variables, during the first 4 months, explained 23 % CO2 variability, whereas, during the rest of the time series, CO2 efflux values are poorly controlled with only 6 %. The observed anomalies of the diffuse CO2 emission rate might be related to pressure changes within the volcanic–hydrothermal system and/or to geostructural changes in the crust due to stress/strain changes caused before and during the earthquakes’ formation, and seem not to be related to the activity of the main crater of Masaya volcano.
, X. H. Shen, C. L. Kang,
Natural Hazards and Earth System Sciences, Volume 13, pp 27-33; doi:10.5194/nhess-13-27-2013

Abstract:
Anomalies of multi-parameters (outgoing longwave radiation, surface latent heat flux, air temperature, relative humidity, and air pressure) before the 12 May 2008 Wenchuan Ms =8.0 earthquake were discussed in order to obtain the seismic precursors. Multi-parameter data were computed based on multi-year background data. The results indicated that these parameters had significant variations prior to this event. The anomaly of outgoing longwave radiation was observed firstly, which gives an early warning. Next were air temperature, relative humidity, and air pressure, which had quasi-simultaneous variations in the basin and the mountain region close to the epicenter. The last was surface latent heat flux, which happened the day before this event. The characteristics of the parameter variations for this event are similar to other earthquakes, which is demonstrated in some other publications. The variations can be attributed to solid earth degassing and chemical reactions in the atmosphere. Additionally, the emission of gases from solid earth into the atmosphere could be ascribed to the tectonic stress of the Wenchuan earthquake.
2012 IEEE International Geoscience and Remote Sensing Symposium pp 7504-7507; doi:10.1109/igarss.2012.6351896

Abstract:
Robust seismic signals around the globe could estimate the gross nature of earthquakes, but the details are usually unclear due to the lack of near-field observations. Although ground measurements, e.g., GNSS/InSAR and strong motion measurements, provide unique insights on the kinematic rupture and nature of the earthquake, but the temporal-spatial resolutions are still limited. In this paper, GNSS atmospheric seismology is proposed and a case study of the 2008 Wenchuan earthquake is performed using ground GNSS measurements. Significant ionospheric disturbances are found at continuous GNSS sites near the epicenter with an intensive N-shape shock-acoustic wave propagating south-eastward, almost consisting with seismometer, indicating that the co-seismic ionospheric TEC disturbances were mainly derived from the main shock. Furthermore, the co-seismic tropospheric anomalies during the mainshock are also found, mainly in the zenith hydrostatic delay component (ZHD), which is supported by the same pattern of surface observed atmospheric pressure changes at co-located GNSS site that are driven by the ground-coupled air waves from ground vertical motion of seismic waves propagating. Therefore, the co-seismic atmospheric disturbances indicate again the acoustic coupling effect of the atmosphere and solid-Earth with air wave propagation from the ground to the top atmosphere.
E. Lagios, G. Sideris, F. Zervos, P. Tsourlos, R. A. Nicholson, Al. Ponomarev, B. Salov, S. Balassanian, H. Petrosyan, S. Bushati, et al.
Published: 1 January 2000
Landslides in Sensitive Clays pp 261-270; doi:10.1007/978-94-015-9544-5_25

Abstract:
Earthquakes are a major natural hazard in numerous parts of the world, and research into precursor signals of seismic activity has mobilised the scientific community for many years. Since earthquakes are a physical phenomenon, attempts for predicting these events in terms of date, magnitude and epicenter have traditionally called upon geophysical methods (seismology, deformation of the ground, electrical methods, etc.). In order to understand more the underlying processes involved, it is necessary to undertake extended periods of monitoring of individual gases at one or more locations, and statistically analyze the compositional data in relation to the observed seismic activity and the effects of extraneous variables. These geophysical anomalies indicate that the faults are zones of weakness acting as channels for deep degassing processes. Numerous successes in forecasting were subsequently recorded through the study of radon emanation in the soils and ground waters of seismic zones. Research into earthquake precursor signals requires continuous instrument surveillance of the selected geophysical parameters. The final objective of this research work is to be able to estimate and prognoses a seismic event. Throughout a one-year period of our research work, we have collected sufficient soil-gas data over long periods at one or more recognized seismically active localities in Greece, Russia, Armenia, and Albania as a preliminary work to establishing a capability for earthquake prediction based on variations in soil gas composition. With the already studied results we are able to demonstrate the viability of the technique, followed by establishment of permanent monitoring stations. The information obtained from these surveys will be compared to data from on-going parallel studies in Greece where all data will be collected via satellite in real-time. Emphasis will be placed on the development of methodology and software suitable for the extended monitoring of gas composition on-site, supported by laboratory determinations to validate the field data where necessary. A number of data loggers (i.e. transducers/detectors) have already been installed at specific selected locations (base stations). Each base station includes a data-logger with which a number of geological parameters are detected. The data are transmitted to a modem, which is directly attached to the INMARSAT global satellite communication system. With the above mentioned multi-disciplinary approach we intend to establish a permanent central data acquisition-broadcasting system with a continuous monitoring of radon, water table level, groundwater temperature, atmospheric temperature and pressure, carbon dioxide, helium, nitrogen, etc.
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