Precursory Information Research Articles

Thermal IR satellite data application for earthquake research in Pakistan

The scientific progress in space research indicates earthquake-related processes of surface temperature growth, gas/aerosol exhalation and electromagnetic disturbances in the ionosphere prior to seismic activity. Among them surface temperature growth calculated using the satellite thermal infrared images carries valuable earthquake precursory information for near/distant earthquakes. Previous studies have concluded that such information can appear few days before the occurrence of an earthquake. The objective of this study is to use MODIS thermal imagery data for precursory analysis of Kashmir (Oct 8, 2005; Mw 7.6; 26 km), Ziarat (Oct 28, 2008; Mw 6.4; 13 km) and Dalbandin (Jan 18, 2011; Mw 7.2; 69 km) earthquakes. Our results suggest that there exists an evident correlation of Land Surface Temperature (thermal; LST) anomalies with seismic activity. In particular, a rise of 3–10 °C in LST is observed 6, 4 and 14 days prior to Kashmir, Ziarat and Dalbandin earthquakes. In order to further elaborate our findings, we have presented a comparative and percentile analysis of daily and five years averaged LST for a selected time window with respect to the month of earthquake occurrence. Our comparative analyses of daily and five years averaged LST show a significant change of 6.5–7.9 °C for Kashmir, 8.0–8.1 °C for Ziarat and 2.7–5.4 °C for Dalbandin earthquakes. This significant change has high percentile values for the selected events i.e. 70–100% for Kashmir, 87–100% for Ziarat and 84–100% for Dalbandin earthquakes. We expect that such consistent results may help in devising an optimal earthquake forecasting strategy and to mitigate the effect of associated seismic hazards.

Multiparameter Monitoring and Prevention of Fault-Slip Rock Burst

Fault-slip rock burst is one type of the tectonic rock burst during mining. A detailed understanding of the precursory information of fault-slip rock burst and implementation of monitoring and early warning systems, as well as pressure relief measures, are essential to safety production in deep mines. This paper first establishes a mechanical model of stick-slip instability in fault-slip rock bursts and then reveals the failure characteristics of the instability. Then, change rule of mining-induced stress and microseismic signals before the occurrence of fault-slip rock burst are proposed, and multiparameter integrated early warning methods including mining-induced stress and energy are established. Finally, pressure relief methods targeting large-diameter boreholes and coal seam infusion are presented in accordance with the occurrence mechanism of fault-slip rock burst. The research results have been successfully applied in working faces 2310 of the Suncun Coal Mine, and the safety of the mine has been enhanced. These research results improve the theory of fault-slip rock burst mechanisms and provide the basis for prediction and forecasting, as well as pressure relief, of fault-slip rock bursts.

Potential loess landslide deformation monitoring using L-band SAR interferometry

Multi-temporal InSAR technique can implement continuous earth surface deformation detection with long time scale and wide geographical coverage. In this paper, we first employ the Small Baseline Subset method to survey potential landslides in Guide County, Qinghai Province, which is identified as a loess landslide prone area for geological and climate conditions. Two anomalous deformation regions are detected by L-band Phased Array and L-band Synthetic Aperture Radar stacks. Then, qualitative and quantitative evaluations of the measuring points are given for understanding the distribution regularity of deformation. Finally, preliminary correlation between the time-series deformation and triggering factors is analyzed to explore the driving mechanism for landslide movement. The results demonstrate that L-band SAR has high potential in landslide monitoring applications and can be used as the basis for landslide recognizing, precursory information extracting, and early warning.

Resistivity and thermal infrared precursors associated with cemented backfill mass

The stability of cemented backfill mass is important to keep miners and equipment safe in underground backfill miming. The stress-strain behavior, resistivity and thermal infrared (TIR) characteristics of backfill mass under uniaxial compression were investigated. The monitoring system consisted of a TIR observation system, a stress-strain monitoring system and a resistivity measurement system. Precursory information for impending failure of cemented backfill mass was collected, including TIR, strain and resistivity precursors. The sensitivity and difference of different monitoring information to the same failure event were compared. The results show that the time-space evolution process of the resistivity and TIR is basically the same as the whole process from compression deformation to failure of backfill mass, and the time variation of resistivity and TIR is obviously characterized by stage. The resistivity precursor turns out earlier than the TIR and the strain. The resistivity relation with loading compression is anti-symmetry, decreasing as the compression stress increases before the peak strength of backfill mass. However, when the backfill mass enters into the phase of failure, the resistivity starts to increase as the stress increases. The change of the resistivity growth direction can be regarded as the resistivity-caution-point for the failure of backfill mass under uniaxial compression. It is also indicated that the TIR information mainly represents the surface temperature evolution in the process of compression before the backfill enters into the plastic-yield state. It can be a valuable tool to obtain the precursors for failure of cemented backfill mass for backfill mines.

An Ensemble Approach for Improved Short-to-Intermediate-Term Seismic Potential Evaluation

Pattern informatics (PI), load/unload response ratio (LURR), state vector (SV), and accelerating moment release (AMR) are four previously unrelated subjects, which are sensitive, in varying ways, to the earthquake’s source. Previous studies have indicated that the spatial extent of the stress perturbation caused by an earthquake scales with the moment of the event, allowing us to combine these methods for seismic hazard evaluation. The longrange earthquake forecasting method PI is applied to search for the seismic hotspots and identify the areas where large earthquake could be expected. And the LURR and SV methods are adopted to assess short-to-intermediate-term seismic potential in each of the critical regions derived from the PI hotspots, while the AMR method is used to provide us with asymptotic estimates of time and magnitude of the potential earthquakes. This new approach, by combining the LURR, SV and AMR methods with the choice of identified area of PI hotspots, is devised to augment current techniques for seismic hazard estimation. Using the approach, we tested the strong earthquakes occurred in Yunnan–Sichuan region, China between January 1, 2013 and December 31, 2014. We found that most of the large earthquakes, especially the earthquakes with magnitude greater than 6.0 occurred in the seismic hazard regions predicted. Similar results have been obtained in the prediction of annual earthquake tendency in Chinese mainland in 2014 and 2015. The studies evidenced that the ensemble approach could be a useful tool to detect short-to-intermediate-term precursory information of future large earthquakes.

An Empirical Study on E-Learning versus Traditional Learning among Electronics Engineering Students

In academia, it appears that many lecturers are still contented in using traditional lecturing methods. Cultivating the use of e-learning requires proper understanding of its difference with traditional learning. In this study, the difference between e-learning with traditional learning was descriptively and empirically investigated, with an emphasis on a module in Electronics Engineering known as Fundamentals of Operational Amplifier. This research involved first-year electronics engineering students from the Faculty of Engineering and Technology, Multimedia University Malaysia. Upon completion of the module, they were asked to participate in a survey and quiz. The data collected were analysed using the normality, reliability and Analysis Of Variance (ANOVA) tests. It was found that e-learners had significantly different results compared to traditional learners. They also exhibited better performance and agreeability in the quiz and survey respectively. In concurrence with the findings of previous researchers, this study suggested that graphical lessons can have a substantial effect on the acceptance of e-learning. The findings of this study can be used to not only improve the course design on Fundamentals of Operational Amplifier but also as a platform to develop greater and more effective learning outcomes in Electronics Engineering and other fields. Generally, although more analyses may be required to verify the existing findings in e-learning, this study can still serve as precursory information regarding the flexibility and effectiveness of e-learning in electronics engineering courses.

Experimental Study on Conductivity Anisotropy of Limestone Considering the Bedding Directional Effect in the Whole Process of Uniaxial Compression.

Experimental studies were conducted on the changes of the potential differences in different directions during the uniaxial compression on limestone samples parallel and normal to the bedding plane. In the test, electric current was supplied at both ends of the samples, and concurrent measurement was conducted in four measuring lines at a 45-degree angle to each other. First, the change laws of the potential differences in different directions and the similarities and differences of rock samples were summarized. In regards to the uniaxial compression properties and crack growth, the above-mentioned similarities and differences were further analyzed. Then, the anisotropy factor was introduced to further explore the response characteristics. It was found that the anisotropic changes of rock samples went through three stages during the uniaxial compression process, providing a reference for describing the properties in different failure stages of rock samples and obtaining precursory information about the fracture. Besides, the relationship between the peak stress and initial potential difference in a direction normal to the current direction was obtained by means of data fitting, providing a new method of predicting the uniaxial compressive strength of rock samples. According to the preceding analysis, this paper studied rock anisotropy by considering the bedding directional effect in terms of conductivity and provided a reference for subsequent study on rock materials’ properties and engineering practices.

Landslide monitoring in southwestern China via time-lapse electrical resistivity tomography

The dynamic monitoring of landslides in engineering geology has focused on the correlation among landslide stability, rainwater infiltration, and subsurface hydrogeology. However, the understanding of this complicated correlation is still poor and inadequate. Thus, in this study, we investigated a typical landslide in southwestern China via time-lapse electrical resistivity tomography (TLERT) in November 2013 and August 2014. We studied landslide mechanisms based on the spatiotemporal characteristics of surface water infiltration and flow within the landslide body. Combined with borehole data, inverted resistivity models accurately defined the interface between Quaternary sediments and bedrock. Preferential flow pathways attributed to fracture zones and fissures were also delineated. In addition, we found that surface water permeates through these pathways into the slipping mass and drains away as fissure water in the fractured bedrock, probably causing the weakly weathered layer to gradually soften and erode, eventually leading to a landslide. Clearly, TLERT dynamic monitoring can provide precursory information of critical sliding and can be used in landslide stability analysis and prediction.

Characteristic Point of the Relatively Quiet Period for Limestone Failure Under Uniaxial Compression

Abstract In view of the precursory characteristic point of limestone failure under uniaxial compression, the underlying mechanisms are not sufficiently clear. Experimental studies examining the acoustic emission (AE) characteristics of the complete limestone failure process have been carried out under uniaxial compression. The experimental results, including accumulative AE counts, the curve of stress and strain, AE rate and stress-time, AE energy rate and stress-time, AE amplitude-time, and AE frequency- time were obtained in detail. The experimental results clearly indicate that AE activities of the samples were generated during the entire process of uniaxial compression. However, the abnormal AE activities appeared in the late stage of the unstable crack propagation phase. These parameters, such as the AE rate, AE energy rate, AE amplitudes, and AE frequencies, were observed to decrease sharply after a relatively quiet period. However, the accumulative AE counts remained at nearly constant values. Stress passed through the quiet period quickly before the peak stress, where the AE activities were enhanced. The AE rate increased suddenly and AE energy rate rose rapidly when the stress reached the peak stress of the samples. As a consequence, the relatively quiet period could be used as the precursory information of rock failure, and the starting point of a relatively quiet period could be predicted as a precursory characteristic point of rock failure. The start point of the relatively quiet period was approximately located in the range of 88 to 98 % of the peak stress.

Regularity and mechanism of coal resistivity response with different conductive characteristics in complete stress–strain process

The stress, strain as well as resistivity of coal during uniaxial compression process were tested based on self-built real-time testing system of loaded coal resistivity. Furthermore, the coal resistivity regularity and mechanism were analyzed at different stages of complete stress–strain process, which includes the two kinds of coal body with typical conductive characteristics. The results indicate that coal resistivity with different conductive characteristics has different change rules in complete stress–strain process. It is mainly represented at the densification and flexibility phases before dilatation occurs. The variation of resistivity can be divided into two kinds, named down and up. Dilatation of coal samples occurred between 66%σmax and 87%σmax. Because of dilatation, coal resistivity involves sudden change. The overall representation is shifting from reducing into improving or from slow improving into accelerated improving. Thus, coal resistivity always shows an increasing tendency at the plastic stage. After peak stress, coal body enters into failure stage. The expanding and communicating of macro fracture causes further improvement of coal resistivity. The maximum value of resistivity rangeability named λ reached 3.49. Through making real-time monitoring on coal resistivity, variation rules of resistivity can be deemed as precursory information so as to reflect the dilatation and sudden change before coal body reaches buckling failure, which can provide a new technological means for forecasting the dynamic disaster of coal petrography.

Reverse bi-orthogonal wavelets & fuzzy classifiers for the automatic detection of spike waves in the EEG of the hypoxic ischemic pre-term fetal sheep.

There exists a 6-8 hour window of opportunity for the treatment of perinatal Hypoxic-Ischemic Encephalopathy (HIE) following the original insult after which significant irreversible brain injury manifests leading to debilitating neurological conditions such as epilepsy and cerebral palsy. At present, there are no identified biomarkers in the electroencephalogram (EEG) that are currently being used to help classify if a HIE insult has occurred or not. However, high frequency micro-scale transients in the form of spikes, sharp waves and slow waves appear in the EEG, post insult, that could provide precursory information whether a HIE insult has occurred or not. This paper describes the superiority of using reverse bi-orthogonal wavelets (RBIO-WT), in the form of the rbio2.8 mother wavelet, in conjunction with a Type-1 Fuzzy Logic System (Type-I FLS) classifier for accurate micro-scale spike wave transient detection in the EEG of Pre-term Fetal Sheep. The algorithm performance for spike detection was assessed over the most critical time period of 25 minutes within the first 8 hours, post occlusion using an in utero fetal sheep model. Obtained results demonstrate that the suggested algorithm detected spikes with a considerably high overall performance of 99.25% using the developed RBIO-WT Type-I FLS.

Statistical Evaluation of Efficiency and Possibility of Earthquake Predictions with Gravity Field Variation and its Analytic Signal in Western China

This paper aimed at assessing gravity variations as precursors for earthquake prediction in the Tibet (Xizang)-Qinghai-Xinjiang-Sichuan Region, western China. We here take a statistical approach to evaluate efficiency and possibility of earthquake prediction. We used the most recent spatiotemporal gravity field variation datasets of 2002–2008 for the region that were provided by the Crustal Movement Observation Network of China (CMONC). The datasets were space sparse and time discrete. In 2007–2010, 13 earthquakes (>M s 6.0) occurred in the region. The observed gravity variations have a statistical correlation with the occurrence of these earthquakes through the Molchan error diagram tests that lead to alarms over a good fraction of space–time. The results show that the prediction efficiency of amplitude of analytic signal of gravity variations is better than seismicity rate model and THD and absolute value of gravity variation, implying that gravity variations before earthquake may include precursory information of future large earthquakes.

Development of a Combination Approach for Seismic Hazard Evaluation

We developed a synth esis approach to augment current techniques for seismic hazard evaluation by combining four previously unrelated subjects: the pattern informatics (PI), load/unload response ratio (LURR), state vector (SV), and accelerating moment release (AMR) methods. Since the PI is proposed in the premise that the change in the seismicity rate is a proxy for the change in the tectonic stress, this method is used to quantify localized changes surrounding the epicenters of large earthquakes to objectively quantify the anomalous areas (hot spots) of the upcoming events. On the short-to-intermediate-term estimation, we apply the LURR, SV, and AMR methods to examine the hazard regions derived from the PI hot spots. A predictive study of the 2014 earthquake tendency in Chinese mainland, using the seismic data from 1970-01-01 to 2014-10-01, shows that, during Jan 01 to Oct 31, 2014, most of the M > 5.0 earthquakes, especially the Feb 12 M7.3 Yutian, May 30 M6.1 Yingjiang, Aug. 03 M6.5 Ludian, and Oct 07 M6.6 earthquakes, occurred in the seismic hazard regions predicted. Comparing the predictions produced by the PI and combination approaches, it is clear that, by using the combination approach, we can screen out the false-alarm regions from the PI estimation, without reducing the hit rate, and therefore effectively augment the predictive power of current techniques. This provided evidence that the multi-method combination approach may be a useful tool to detect precursory information of future large earthquakes.

Study on Mine Rock Disaster Based on Acoustic Emission Technology

Study the effect of water on the acoustic emission quiet period before the destruction of rock based on the uniaxial loading experiment of acoustic emission of drying, natural and saturated basalt. The results show that the drying, natural and saturated basalt have AE quiet period before rupture. The load level of AE quiet period quiet period increase and shorter duration, and quiet period recognition is more difficult.AE quiet period, the AE event rate maintain per 10, but AE energy rate is not calm and characterized by accelerated release, and the release rate decreases with the increasing of water content. Due to full water characteristics of the actual mining basalt and the complexity of its fracture, the dominant frequency the AE rate of mutational characteristics and the AE event rate calm characteristic can be combined used to obtain information. The rate of mutation phenomenon before AE quiet period can be used as early warning information of saturated basalt rupture, and AE quiet period can be used as precursory information of saturated basalt rupture.

Statistical analysis of ULF seismomagnetic phenomena at Kakioka, Japan, during 2001–2010

AbstractTo clarify and verify the ultralow frequency (ULF) seismomagnetic phenomena, we have performed statistical studies on the geomagnetic data observed at the Kakioka (KAK) station, Japan, during 2001–2010. We investigated the energy of ULF geomagnetic signals of the frequency around 0.01 Hz using wavelet transform analysis. To minimize the influences of artificial noises and global geomagnetic perturbations, we used only the geomagnetic data observed at nighttime (LT 2:30 A.M. to 4:00 A.M.) and utilized observations from a remote station, Kanoya, as a reference. Statistical results of superposed epoch analysis have indicated that ULF magnetic anomalies are more likely to appear before sizable earthquake events (Es > 108) rather than after them, especially 6–15 days before the events. Further statistical investigations show clearly that the ULF geomagnetic anomalies at KAK station are more sensitive to larger and closer events. Finally, we have evaluated the precursory information of ULF geomagnetic signals for local sizable earthquakes using Molchan's error diagram. The probability gain is around 1.6 against a Poisson model. The above results have indicated that the ULF seismomagnetic phenomena at KAK clearly contain precursory information and have a possibility of improving the forecasting of large earthquakes.

Study of the Precursory Rules of a Deformation Localization of Coal Specimens

The instability failure of coal and rock mass occur frequently in deep mining. However, this destruction occurs with abnormal intensity and suddenness, with hardly any obvious macro precursors. The ability to extract this precursory information and make certain the relationship among the parameters is therefore important. During the process of instability and failure of coal samples, the evolution characteristics of deformation field were monitored by digital image correlation system. Base on the researches, the appearance of the deformation localization band could be divided into three time periods for the samples which all had splitting failure. During period I, the relative sliding component increased rapidly. During period II, the relative tension component increased rapidly. During period III, both the relative tension and relative sliding components increased rapidly.

Improving Situational Awareness for Precursory Data Classification using Attribute Rough Set Reduction Approach

The task of modeling the distribution of a large number of earthquake events with frequent tremors detected prior to a main shock presents us unique challenges to model a robust classifier tool for rapid responses are needed in order to address victims. We have designed using a relational database for running a geophysical modeling application after connecting database record of all clusters of foreshock events from (1998-2010) for a complete catalog of seismicity analysis for the Himalayan basin. by Nath et al,2010. This paper develops a reduced rough set analysis method and implements this novel structure and reasoning process for foreshock cluster forecasting. In this study, we developed a reusable information technology infrastructure, called Efficient Machine Readable for Emergency Text Selection(EMRETS). The association and importance of precursory information in reference to earthquake rupture analysis is found out through attribute reduction based on rough set analysis. Secondly, find the importance of attributes through information entropy is a novel approach for high dimensional complex polynomial problems pre- dominant in geo-physical research and prospecting. Thirdly, we discuss the reducible indiscernible matrix and decision rule generation for a particular set of geographical co-ordinates leading to the spatial discovery of future earthquake having prior foreshock. This paper proposes a framework for extracting, classifying, analyzing, and presenting semi-structured catalog data sources through feature representation and selection.

Assessing the potential improvement in short‐term earthquake forecasts from incorporation of GPS data

AbstractWe validate that changes of ground deformation recorded by GPS contain useful information for earthquake forecasting. A moving rate of variation filter is used to extract short‐term signals from GPS time series in New Zealand, California, and Japan. The precursory information of these signals for large earthquakes is evaluated using Molchan's error diagram. The results suggest that the GPS signals provide a probability gain of 2–4 for forecasting large earthquakes against a Poisson model. Further tests show that the GPS signals are not triggered by large earthquakes, and that the probability gain is not derived from forecasting aftershocks. This demonstrates that noncatalog information, such as GPS data, can be used to augment probabilistic models based on seismic catalog data to improve forecasting of large earthquakes.

Characteristic Changes of Scale Invariance of Seismicity Prior to Large Earthquakes: A Constructive Review

Recently, research on the characteristic changes of scale invariance of seismicity before large earthquakes has received considerable attention. However, in some circumstances, it is not easy to obtain these characteristic changes because the features of seismicity in different regions are various. In this paper, we firstly introduced some important research developments of the characteristic changes of scale invariance of seismicity before large earthquakes, which are of particular importance to the researchers in earthquake forecasting and seismic activity. We secondly discussed the strengths and weaknesses of different scale invariance methods such as the local scaling property, the multifractal spectrum, the Hurst exponent analysis, and the correlation dimension. We finally came up with a constructive suggestion for the research strategy in this topic. Our suggestion is that when people try to obtain the precursory information before large earthquakes or to study the fractal property of seismicity by means of the previous scale invariance methods, the strengths and weaknesses of these methods have to be taken into consideration for the purpose of increasing research efficiency. If they do not consider the strengths and weaknesses of these methods, the efficiency of their research might greatly decrease.

Scale invariance in complex seismic system and its uses in gaining precursory information before large earthquakes: Importance of methodology

Research on precursory information about the scale invariance of seismicity before large earthquakes has been an interesting topic for geophysicists in recent years. However, in some cases, it is difficult to capture this precursory information. Our study results show that seeking a pertinent selection of methodology is really needed for the purpose of gaining precursory information in the application of the analytical methods related to scale invariance. We investigated the scale invariance of the interevent time series of the seismic sequences for the Minle and Songpan regions in China by applying the methods of R/S Hurst analysis, local scaling property, correlation dimension, and generalized dimension spectrum. It is indicated that there are clearly precursory changes of local scaling property before the Minle M6.1 and Songpan M7.2 earthquakes, as well as precursory changes of the Hurst exponent and generalized dimension spectrum before the Songpan M7.2 earthquakes, while there are no clearly precursory changes of the Hurst exponent and generalized dimension spectrum before the Minle M6.1 earthquake, as well as the precursory change of the correlation dimension before the above large earthquakes, which signifies that there is a difference in the capability for capturing precursory information among the above four methods. This result suggests that the selection of an appropriate methodology is quite necessary to obtain the precursory information on the scale invariance in the use of the above four methods. If we do not select an appropriate methodology, we might not obtain any precursory information.