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Wu, Lixin
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Wu, Lixin
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Wu, L. X.
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- PublicationRestrictedIMPORTANCE OF LITHOSPHERE-COVERSPHERE-ATMOSPHERE COUPLING TO EARTHQUAKE ANOMALY RECOGNITION(IEEE, 2012-07-22)
; ; ; ; ; ;Wu, L.; Beijing Normal University, Beijing, 100875, China ;Qin, K.; China University of Mining and Technology (Beijing), Beijing, 10083, China ;Liu, S.; Northeastern University, Shenyang, 110004, China ;De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Cianchini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; ; The GEOSS under construction is providing space-,aero-,ground/sea-based multiple observations on planet Earth for the seismogenic process monitoring and earthquake precaution. The stress enhancement and energy accumulation in seismic activity area change locally the physical parameters of lithosphere with the developing of a series of effects that can comprise most of the following ones: initial cracks, the fracturing of rockmass, the changing of electromagnetic properties, the decreasing of dielectric constant, the re-activation of P-holes, the leaking of poregas, and the rise of water-level. The physical states of coversphere and atmosphere are to be affected due to the lithosphere-coversphere-atmosphere (LCA) coupling, and the signals from the underground, surface, and atmosphere to satellites are to be changed with parameter anomaly. We suggested that the LCA coupling is important for understanding GEOSS observations, especially for earthquake anomaly recognition (EAR). Using deviation-time-space-thermal (DTS-T) method for EAR, three recent major earthquakes (2009 Italy L'Aquila earthquake, 2010 China Yushu earthquake and 2010-2011 New Zealand earthquake sequence) are taken as typical cases for analysis to the multi-parameters anomalies, preceding the shocking, with quasi-synchronism and geoconsistency. The specific LCA coupling effects related with the earthquakes are also discussed in brief.573 24 - PublicationOpen AccessGeosphere coupling and hydrothermal anomalies before the 2009 Mw 6.3 L'Aquila earthquake in ItalyThe earthquake anomalies associated with the 6 April 2009 Mw 6.3 L’Aquila earthquake have been widely reported. Nevertheless,the reported anomalies have not been so far synergically analyzed to interpret or prove the potential lithosphere–coversphere–atmosphere coupling (LCAC) process. Previous studies on b value (a seismicity parameter from Gutenberg–Richter law) are also insufficient. In this work, the spatiotemporal evolution of several hydrothermal parameters related to the coversphere and atmosphere, including soil moisture, soil temperature, near-surface air temperature, and precipitable water, was comprehensively investigated. Air temperature and atmospheric aerosol were also statistically analyzed in time series with ground observations. An abnormal enhancement of aerosol occurred on 30 March 2009 and thus proved quasi-synchronous anomalies among the hydrothermal parameters from 29 to 31 March in particular places geo-related to tectonic thrusts and local topography. The three-dimensional (3-D) visualization analysis of b value revealed that regional stress accumulated to a high level, particularly in the L’Aquila basin and around regional large thrusts. Finally, the coupling effects of geospheres were discussed, and a conceptual LCAC mode was proposed to interpret the possible mechanisms of the multiple quasi-synchronous anomalies preceding the L’Aquila earthquake. Results indicate that CO2-rich fluids in deep crust might have played a significant role in the local LCAC process.
147 110 - PublicationRestrictedMECHANISMS AND RELATIONSHIP TO SOIL MOISTURE OF SURFACE LATENT HEAT FLUX ANOMALY BEFORE INLAND EARTHQUAKES(IEEE, 2012-07-22)
; ; ; ; ; ;Qin, K.; China University of Mining and Technology (Beijing), Beijing, 10083 ;Wu, L.; Beijing Normal University, Beijing, 100875 ;Liu, S.; Northeastern University, Shenyang, 110004 ;De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Cianchini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; ; The anomaly of SLHF, which is a key component of the Earth's energy balance and represents the heat flux from the Earth's surface to the atmosphere associated with evaporation or transpiration of water on the surface and subsequent condensation of water vapor in the troposphere, has been widely reported as a possible earthquake precursor. The causes are generally attributed to the increase in infrared thermal (IR) temperature and the air ionization produced by increased emanation of radon from the Earth's crust. In this paper, the theoretical analysis and case study show that there is close relationship between soil moisture and SLHF anomalies. For inland earthquakes, the increase of soil moisture due to the rising of groundwater level will bring with higher potential evaporation, leading to the increase of latent heat flux. Further study with more accurate soil moisture product after the new satellite mission will help us to better understand the influence of soil moisture on SLHF variation and their relations with seismogenic process.328 58 - PublicationOpen AccessToward a possible next geomagnetic transition ?(2013-11-28)
; ; ; ;De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Qamili, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Wu, L.; ; The geomagnetic field is subject to possible reversals or excursions of polarity during its temporal evolution. Considering that: (a) in the last 83 million yr the typical average time between one reversal and the next (the so-called chron) is around 400 000 yr, (b) the last reversal occurred around 780 000 yr ago, (c) more excursions (rapid changes in polarity) can occur within the same chron and (d) the geomagnetic field dipole is currently decreasing, a possible imminent geomagnetic reversal or excursion would not be completely unexpected. In that case, such a phenomenon would represent one of the very few natural hazards that are really global. The South Atlantic Anomaly (SAA) is a great depression of the geomagnetic field strength at the Earth’s surface, caused by a reverse magnetic flux in the terrestrial outer core. In analogy with critical point phenomena characterized by some cumulative quantity, we fit the surface extent of this anomaly over the last 400 yr with power law or logarithmic functions in reverse time, also decorated by logperiodic oscillations, whose final singularity (a critical point tc) reveals a great change in the near future (2034±3 yr), when the SAA area reaches almost a hemisphere. An interesting aspect that has recently been found is the possible direct connection between the SAA and the global mean sea level (GSL). That the GSL is somehow connected with SAA is also confirmed by the similar result when an analogous critical-like fit is performed over GSL: the corresponding critical point (2033±11 yr) agrees, within the estimated errors, with the value found for the SAA. From this result, we point out the intriguing conjecture that tc would be the time of no return, after which the geomagnetic field could fall into an irreversible process of a global geomagnetic transition that could be a reversal or excursion of polarity.663 1331 - PublicationOpen AccessPrecise Topographic Model Assisted Slope Displacement Retrieval from Small Baseline Subsets Results: Case Study over a High and Steep Mining Slope(2020-11-21)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Due to the intrinsic side-looking geometry of synthetic aperture radar (SAR), time series interferometric SAR is only able to monitor displacements in line-of-sight (LOS) direction, which limits the accuracy of displacement measurement in landslide monitoring. This is because the LOS displacement is only a three dimensional projection of real displacement of a certain ground object. Targeting at this problem, a precise digital elevation model (DEM) assisted slope displacement retrieval method is proposed and applied to a case study over the high and steep slope of the Dagushan open pit mine. In the case study, the precise DEM generated by laser scanning is first used to minimize topographic residuals in small baseline subsets analysis. Then, the LOS displacements are converted to slope direction with assistance of the precise DEM. By comparing with ground measurements, relative root mean square errors (RMSE) of the estimated slope displacements reach approximately 12-13% for the ascending orbit, and 5.4-9.2% for the descending orbit in our study area. In order to validate the experimental results, comparison with microseism monitoring results is also conducted. Moreover, both results have found that the largest slope displacements occur on the slope part, with elevations varying from -138 m to -210 m, which corresponds to the landslide area. Moreover, there is a certain correlation with precipitation, as revealed by the displacement time series. The outcome of this article shows that rock mass structure, lithology, and precipitation are main factors affecting the stability of high and steep mining slopes.191 33 - PublicationOpen AccessMagnetic transfer function entropy and the 2009 Mw = 6.3 L’Aquila earthquake (Central Italy)(2012-07-23)
; ; ; ; ; ;Cianchini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Barraclough, D. R.; British Geological Survey, Edinburgh, UK ;Wu, L. X.; Academy of Disaster Reduction and Emergency Management, Beijing Normal University, China ;Qin, K.; China University of Mining and Technology, Beijing, China; ; ; ; With the aim of obtaining a deeper knowledge of the physical phenomena associated with the 2009 L’Aquila (Central Italy) seismic sequence, culminating with a Mw = 6.3 earthquake on 6 April 2009, and possibly of identifying some kind of earthquake-related magnetic or geoelectric anomaly, we analyse the geomagnetic field components measured at the magnetic observatory of L’Aquila and their variations in time. In particular, trends of magnetic transfer functions in the years 2006–2010 are inspected. They are calculated from the horizontal to vertical magnetic component ratio in the frequency domain, and are very sensitive to deep and lateral geoelectric characteristics of the measurement site. Entropy analysis, carried out from the transfer functions with the so called transfer function entropy, points out clear temporal burst regimes of a few distinct harmonics preceding the main shock of the seismic sequence. A possible explanation is that they could be related to deep fluid migrations and/or to variations in the micro-/meso-fracturing that affected significantly the conductivity (ordered/disordered) distribution in a large lithospheric volume under the seismogenic layer below L’Aquila area. This interpretation is also supported by the analysis of hypocentres depths before the main shock occurrence.305 151 - PublicationOpen AccessPreliminary analysis of surface temperature anomalies that preceded the two major Emilia 2012 earthquakes (Italy)(2012)
; ; ; ; ;Qin, K.; China University of Mining and Technology, College of Geosciences and Surveying Engineering, Beijing, China ;Wu, L. X.; China University of Mining and Technology, School of Environment Science and Spatial Informatics, Xuzhou, China ;De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Cianchini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; In the 1980's, from an analysis of satellite images, Russian scientists reported on a short-term thermal infrared radiation enhancement that occurred before some medium-to-large earthquakes in central Asia [Gorny et al. 1988]. Since then, many researchers have been studying earthquake thermal anomalies with satellite remote sensing data [Qiang et al. 1991, Tronin 1996, Tramutoli et al. 2001, Ouzounov and Freund 2004, Saraf and Choudhury 2004, Aliano et al. 2008, Blackett et al. 2011]. Recently, abnormal surface latent heat flux [Dey and Singh 2003, Cervone et al. 2005, Qin et al. 2009, Qin et al. 2011, Qin et al. 2012], outgoing long-wave radiation [Ouzounov et al. 2007] and microwave radiation [Takashi and Tadashi 2010] have also been shown to precede earthquakes. To investigate the possible physical mechanisms of such satellite thermal anomalies, some studies conducted a series of detecting experiments on rock loaded to fracturing [Wu et al. 2000, Freund 2002, Wu et al. 2002, Wu et al. 2006a, Wu et al. 2006b, Freund et al. 2007], and some hypotheses have been proposed. These have included: leaking of pore-gas, and hence the resulting greenhouse effect [Qiang et al. 1995]; activating and recombining of p-holes during rock deformation [Freund 2002]; release of latent heat due to near-surface air ionization [Pulinets et al. 2006], and stress-induced thermal effects due to friction and fluids [Wu and Liu 2009]. According to the Istituto Nazionale di Geofisica e Vulcanologia (INGV; National Institute of Geophysics and Volcanology), two major earthquakes with almost the same large magnitudes struck northern Italy, on the Po Plain in the Emilia Region. The first hit on May 20, 2012, at 02:03 UTC, with ML 5.9 (44.89 °N, 11.23 °E; 6 km in depth), and the second on May 29, 2012, at 07:00 UTC, with ML 5.8 (44.85 °N, 11.09 °E; 10 km in depth). These caused a total of 27 deaths and widespread damage. In this study, the long-term temperature data from both satellite and ground (with greater emphasis on the satellite data) have been used to determine whether there were thermal anomalies associated with this Emilia 2012 seismic sequence. In particular, the next section will be dedicated to describing both the data and the method of analysis. In Section 3, we provide the more significant results, which we discuss in Section 4, together with the main conclusions. We acknowledge that this work cannot be exhaustive, as it will require more data and analyses. However, although further studies will be welcome, we are confident that we have done the best with the data at our disposal.486 808 - PublicationRestrictedQuasi-synchronous multi-parameter anomalies associated with the 2010–2011 New Zealand earthquake sequence(2012-04-16)
; ; ; ; ; ; ;Qin, K.; College of Geosciences and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing, China ;Wu, L. X.; Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs/Ministry of Education of P.R. China (Beijing Normal University), Beijing, China ;De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Meng, J.; College of Geosciences and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing, China ;Ma, W. Y.; College of Geosciences and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing, China ;Cianchini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; ; ; Positive thermal anomalies about one month before the 3 September 2010 Mw Combining double low line 7.1 New Zealand earthquake and " coincidental" quasi-synchronous fluctuations of GPS displacement were reported. Whether there were similar phenomena associated with the aftershocks? To answer it, the following was investigated: multiple parameters including surface and near-surface air temperature, surface latent heat flux, GPS displacement and soil moisture, using a long-term statistical analysis method. We found that local thermal and deformation anomalies appeared quasi-synchronously in three particular tectonic zones, not only about one month before the mainshock, but also tens of days before the 21 February 2011 Mw Combining double low line 6.3 aftershock, and that the time series of soil moisture on the epicenter pixel had obvious peaks on most of the anomalous days. Based on local tectonic geology, hydrology and meteorology, the particular lithosphere-coversphere-atmosphere coupling mode is interpreted and four mechanisms (magmatic-hydrothermal fluids upwelling, soil moisture increasing, underground pore gases leaking, and positive holes activating and recombining) are discussed.413 96 - PublicationOpen AccessSurface latent heat flux anomalies preceding inland earthquakes in China(2009-10-10)
; ; ; ;Qin, K.; China University of Mining & Technology (Beijing) ;Guo, G.; College of Environmental Science and Traveling, Nanyang Normal University, Nanyang 473061, Henan, China ;Wu, L.; Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs, Ministry of Education (Beijing Normal University), Beijing 100875, China; ; Using data from the National Center for Environmental Prediction (NCEP), the paper analyzed the surface latent heat flux (SLHF) variations for five inland earthquakes occurred in some lake area, moist area and arid area of China during recent years. We used the SLHF daily and monthly data to differentiate the global and seasonal variability from the transient local anomalies. The temporal scale of the observed variations is 1–2 months before and after the earthquakes, and spatial scale is about 10°×10°. The result suggests that the SLHFs adjacent the epicenters all are anomalous high value (>μ+2σ) 8–30 days before the shocks as compared with past several years of data. Different from the abnormal meteorological phenomenon, the distribution of the anomalies was isolated and local, which usually occurred in the epicenter and its adjacent area, or along the fault lines. The increase of SLHF was tightly related with the season which the earthquake occurs in; the maximal (125 W/m2, Pu’er earthquake) and minimal (25 W/m2, Gaize earthquake) anomalies were in summer and winter, respectively. The abundant surface water and groundwater in the epicenter and its adjacent region can provide necessary condition for the change of SLHF. To further confirm the reliability of SLHF anomaly, it is necessary to explore its physical mechanism in depth by more earthquake cases.160 190 - PublicationOpen AccessIs there a one-to-one correspondence between ionospheric anomalies and large earthquakes along Longmenshan faults?(2014)
; ; ; ; ; ;He, L. M.; Shenyang University, China ;Wu, L. X.; Normal Beijing Univ., China ;De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Liu, S. J.; Shenyang University, China ;Yang, Y.; Shenyang University, China; ; ; ; On 12 May 2008, a destructive M8.0 earthquake struck Wenchuan County (31.0 N, 103.4E) in the Longmenshan fault zone of southwestern China. Five years later, on 20 April 2013, another terrible M7.0 earthquake struck Lushan County (30.3 N, 103.0 E) in the same fault area, only 87 km away from the epicenter of the Wenchuan earthquake. In this paper, an integrated wavelet analysis methodology is proposed to detect and diagnose ionospheric total electron content (TEC) anomalies related to seismic activities. Analytic wavelet transform is used to detect ionospheric perturbations, and then cross-wavelet analysis is used to diagnose ionospheric anomalies by gaining further insights into the dynamic relationship between the anomaly variability of ionospheric TEC and geomagnetic indices for the same set of observations. The results show that a significant ionospheric disturbance occurred on 9 May 2008 above the forthcoming epicenter, 3 days prior to the Wenchuan earthquake. However,we did not observe an ionospheric anomaly over the epicenter of the Ya’an earthquake during the 1 month period before the shock. Finally, we discuss the possible interpretations of the different seismo-ionospheric effects for the two similar earthquakes.173 131