Search

The literature often reports space–time relations between the abnormal variations of different kinds of nonseismological (i.e., geophysical, geochemical, and atmospheric) parameters and the occurrence of earthquakes. The integration of such observations with seismological ones could improve the quality of the seismic hazard assessment in the medium‐short term (months to days). Each considered parameter has, in principle, its capabilities to provide useful (and utilizable) information about seismic processes. Therefore, to define a system based on different observations, the first step is to estimate the informative contribution that each considered parameter could provide. In this paper, we will evaluate the potential of Significant Sequence of Thermal Anomalies (SSTAs). In particular, we adopted the broadly used Robust Satellite Techniques (RST) data analysis methodology to identify SSTAs over 11 years (June 2005 to December 2015) of nighttime satellite images acquired by MTSAT satellites over Japan. Aiming at reducing the false‐positive rate, we introduced and tested an innovative configuration of the RST, which is here presented. We executed a correlation analysis between SSTAs and Japanese earthquakes with MJMA ≥ 6 by applying suitable constraints concerning space, time, and magnitude. The analysis highlights (a) the occurrence of just 29 SSTAs in the 11‐year period of observation, (b) 18 SSTAs (i.e., 62%) occur in an apparent space–time relation to earthquakes, and (c) 13 of them occur before the quake. Results of the random test analysis, based on error diagrams, confirm a noncasual correlation between "RST‐based satellite thermal anomalies" and earthquake occurrences. In particular, for MJMA ≥ 6.5 earthquakes, probability gain is up to better than 4.3 as compared with the random guess. Key Points: We present an innovative version of the Robust Satellite Techniques able to reduce the proliferation of false‐positive thermal anomaliesA noncasual relation between satellite thermal anomalies and MJMA ≥ 6 earthquakes affecting Japan in the time span 2005–2015 was foundMultiparametric approach could accelerate the set‐up of a system for time‐dependent assessment of seismic hazard [ABSTRACT FROM AUTHOR]

For more than 13 years a multi-temporal data-analysis method, named Robust Satellite Techniques (RST), has been being applied to satellite Thermal InfraRed (TIR) monitoring of seismically active regions. It gives a clear definition of a TIR anomaly within a validation/confutation scheme devoted to verify if detected anomalies can be associated or not to the time and location of the occurrence of major earthquakes. In this scheme, the confutation part ( i.e. verifying if similar anomalies do not occur in the absence of a significant seismic activity) assumes a role even much important than the usual validation component devoted to verify the presence of anomalous signal transients before (or in association with) specific seismic events. Since 2001, RST approach has been being used to study tens of earthquakes with a wide range of magnitudes (from 4.0 to 7.9) occurred in different continents and in various geo-tectonic settings. In this paper such a long term experience is exploited in order to give a quantitative definition of a significant sequence of TIR anomalies ( SSTA ) in terms of the required space–time continuity constraints ( persistence ), identifying also the different typologies of known spurious sequences of TIR anomalies that have to be excluded from the following validation steps. On the same basis, taking also into account for the physical models proposed for justifying the existence of a correlation between TIR anomalies and earthquakes occurrence, specific validation rules (in line with the ones used by the Collaboratory for the Study of Earthquake Predictability – CSEP – Project) have been defined to drive the validation process. In this work, such an approach is applied for the first time to a long-term dataset of night-time GMS-5/VISSR (Geostationary Meteorological Satellite/Visible and Infrared Spin-Scan Radiometer) TIR measurements, comparing SSTAs and earthquakes with M > 4 which occurred in a wide area around Taiwan, in the month of September of different years (from 1995 to 2002). In this dataset the Chi-Chi earthquake ( M W = 7.6) which occurred on September 20, 1999 represents the major, but not unique, event. The analysis shows that all identified SSTAs occur in the pre-fixed space–time window around (in terms of time and location) earthquakes with M > 4. The false positive rate remains zero even if only earthquakes with M > 4.5 are considered. In the case of the Chi-Chi earthquake, 3 SSTAs were identified (all within the established space–time correlation window), one of them appearing about 2 weeks before and very close to the epicentre of the earthquake just along the associated tectonic lineaments. The wide considered space–time window, together with the high seismicity of the considered area, surely positively conditioned the achieved results, so that further analyses should be carried out by using longer datasets and different geographic areas. However, also considering the coincidence with other (possible) precursor phenomena, independently reported (particularly within the iSTEP project) at the time of the Chi Chi earthquake, achieved results seem already sufficient (at least) to qualify TIR anomalies (identified by RST) among the parameters to be considered in the framework of a multi-parametric approach to a time-Dependent Assessment of Seismic Hazard ( t-DASH ). [ABSTRACT FROM AUTHOR]

This paper explores multi-instrument space-borne observations in order to validate physical concepts of Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) in relation to a selection of major seismic events. In this study we apply some validated techniques to observations in order to identify atmospheric and ionospheric precursors associated with some of recent most destructive earthquakes: M8.6 of March 28, 2005 and M8.5 of Sept. 12, 2007 in Sumatra, and M7.9 of May 12, 2008 in Wenchuan, China. New investigations are also presented concerning these three earthquakes and for the M7.2 of March 2008 in the Xinjiang-Xizang border region, China (the Yutian earthquake). It concerns the ionospheric density, the Global Ionospheric Maps (GIM) of the Total Electron Content (TEC), the Thermal Infra-Red (TIR) anomalies, and the Outgoing Longwave Radiation (OLR) data. It is shown that all these anomalies are identified as short-term precursors, which can be explained by the LAIC concept proposed in [S. Pulinets, D. Ouzounov, J. Asian Earth Sci. 41, 371 (2011)]. [ABSTRACT FROM AUTHOR]

Treating the time dimension (i.e., the 4th dimension) of geospatial parameters, likewise the other dimensions is important for some applications to better understand the possible space-time relations among the physical parameters underlying the dynamics of complex phenomena. In this paper we present the potential of an innovative solution, named 4 Dimensions Environmental ObServation (4DEOS), which is a platform able to handle the 4th dimension in an asynchronous way (i.e., to visualize more signals, holding some of them fixed in the time domain while moving others over time). 4DEOS is based on a Client-Broker-Server architecture for the easy integration and visualization of heterogeneous, asynchronous, geospatial products. The prototype system was evaluated in the case of earthquake prediction studies where the asynchronous visualization of independent observations could allow a timely identification of the spatial correlations appearing at different time lags, which could be missed using other existing 4D Geographic Information System software. [ABSTRACT FROM AUTHOR]

In this study, Earth's emitted Thermal InfraRed (TIR) radiation measured from geostationary satellite sensors has been analyzed by using an original data analysis approach in order to evaluate possible space-time correlation with earthquakes (M=4.0) occurrence. A clear definition of SSTA (Significant Sequence of Thermal Anomaly) concept is given and correlation rules are established in order to evaluate the potential of SSTAs among the parameters to be included in a pre-operational system for time- Dependent Assessment of Seismic Hazard (t-DASH). On the considered time period (July 2012 - June 2013) and testing areas (Italian southern Apennines and Po Plain) a false positive rate lesser than 33% has been obtained. Notwithstanding a missing rate up to 67% (mostly because of the presence of clouds preventing the continuity of observations), as confirmed by other independent studies performed on longer period of time and different geographic areas, seems to strongly support the inclusion of SSTAs [identified by the RST (Robust Satellite Technique) methodology] among the parameters whose continuous monitoring and integration with all the other relevant information available, could strongly improve our present capabilities to dynamically assess seismic hazard in a pre-operational context. [ABSTRACT FROM AUTHOR]

This review paper reports the main contributions and results achieved after more than 30 years of studies on the possible relationships among space-time variation of Earth's thermally emitted radiation, measured by satellite sensors operating in the Thermal InfraRed (TIR) spectral range (8-14 m), and earthquake occurrence. Focus will be given on the different existing methods/models to: 1) discriminate a possible pre-seismic TIR anomaly from all the other TIR signal fluctuations; 2) correlate such anomalies with space, time and magnitude of earthquakes; 3) physically justify such a correlation. [ABSTRACT FROM AUTHOR]