In this paper, the causes of the occurrence of the temperature increase by an impending earthquake of low altitude atmosphere and on the ground surface have been preliminarily expounded through several simulative cont...In this paper, the causes of the occurrence of the temperature increase by an impending earthquake of low altitude atmosphere and on the ground surface have been preliminarily expounded through several simulative controlexperiments. Air polarized by the anomalous atmospheric static electric field is regarded as the primary factor tocreate air temperature increase to a large degree and over a large area in the sunlight. In addition, another causeis considered as the temperature increase effect of “polluted” air.展开更多
Debris flow prediction is one of the important means to reduce the loss caused by debris flow. This paper built a regional prediction model of impending debris flow based on regional environmental background (includi...Debris flow prediction is one of the important means to reduce the loss caused by debris flow. This paper built a regional prediction model of impending debris flow based on regional environmental background (including topography, geology, land use, and etc.), rainfall and debris flow data. A system of regional prediction of impending debris flow was set up on ArcGIS 9.0 platform according to the model. The system used forecast precipitation data of Doppler weather radar and observational precipitation data as its input data. It could provide a prediction about the possibility of debris flow one to three hours before it happened, and was put into use in Liangshan Meteorological Observatory in Sichuan province in the monsoon of 2006.展开更多
Based on repeated comparison studies of broadband digital seismic records before the Wenchuan MS8. 0,Yushu MS7. 1 and Qingchuan MS5. 4 earthquakes,the possible microseismic fluctuations before impending earthquakes we...Based on repeated comparison studies of broadband digital seismic records before the Wenchuan MS8. 0,Yushu MS7. 1 and Qingchuan MS5. 4 earthquakes,the possible microseismic fluctuations before impending earthquakes were preliminarily identified. In order to verify and test this phenomenon,a real-time tracking technical system was established by using continuous waveform records of more than 200 wide-band digital seismic stations in regional networks such as Gansu,Qinghai,Sichuan,Yunnan and Tibet.Through real-time tracking and dynamic monitoring of 24 earthquakes with M≥5. 0 occurring in the Qinghai-Tibetan block during the period of 2012-2014 and the observations of stations in some non-seismic areas,the reproducibility and objectivity of the impending earthquake phenomenon were verified. The main characteristics of the microseismic fluctuation phenomena immediately preceding the strong earthquakes are as follows:(1)the spectrum range is wider,the dominant frequency is 11-16 Hz,and the spectrum shape is more regular;(2)it appears 6-24 days before the earthquake,averaging about 15 days;(3)it is possible to be recorded by the stations within the epicenter distance of 50 km,and the stations with the epicenter distance of more than 50 km generally cannot record it;(4)this phenomenon is directional,i. e. the direction in which the activity degree,N-value,varies significantly may be related to the location of the seismic source,the seismogenic fault and the distribution of aftershocks of the strong earthquake. The preliminary study shows that the impending-earthquakes microseismic phenomena may be related to the pre-activity,micro-vibration and micro-rupture in the source region in the imminent stage,or the microactivity and micro-rupture associated with the active tectonics.展开更多
Mechanism of satellitic thermo-infrared brightness temperature and temperature increasing is studied. Experiments are made with a gas sample taken around the epicenter area. The gas sample is proved to contain green h...Mechanism of satellitic thermo-infrared brightness temperature and temperature increasing is studied. Experiments are made with a gas sample taken around the epicenter area. The gas sample is proved to contain green house gases such as CH<sub>4</sub> and CO<sub>2</sub> which have increased by tens of thousands of times. In addition, lab research also proves that CH<sub>4</sub> and CO<sub>2</sub> can obtain energy under the action of transient electric field and release heat, thus resulting in a temperature increase of 2—6℃. Also a brief account of practices since 1990 is given; altogether 40 short-term and impending earthquake predictions have been made, with 9 precise ones whose three main factors of an earthquake are clearly depicted, and 12 fairly good ones. These predictions include 3 earthquakes of M<sub>s</sub>≥7, 4 of M<sub>s</sub>≥6.0 and the rest are around M<sub>s</sub> 5.0. Yet there are earthquakes left out of prediction. Finally the evolutionary processing characters of satellitic thermo-infrared brightness temperature and temperature increase before展开更多
We deployed four geo-electric monitoring stations in Sichuan and Yunnan provinces from 2004, using the new generation of equipment (PS-100) and technologies to capture the HRT wave earthquake precursor. Before the Wen...We deployed four geo-electric monitoring stations in Sichuan and Yunnan provinces from 2004, using the new generation of equipment (PS-100) and technologies to capture the HRT wave earthquake precursor. Before the Wenchuan Ms8.0 earthquake, we recorded the HRT wave precursor at the only operating station in Hongge (HG, Δ=465 km) and found that significant impending signal had been recorded at the station in the early morning ( 0―5 am) of 12th of May, 2008. The precursor for this earthquake is consistent with precursors recorded for other strong earthquakes. The measured physical properties (geo-resistivity and telluric-current) show tidal wave period oscillations from several days to several months before the earthquakes and the amplitude of such HT oscillation increases significantly towards the occurrence of an earthquake. These HT and RT waves from the epicenter have a causal relationship with the earthquakes that happened several days later. The arrival time of two RT waves is proportional to the distance from the station to the epicenter. The estimated natural decay of the amplitude is correlated with the natural period (T0) of the earthquake fault, which is proportional to the fault length. From this relationship, we can predict the earthquake magnitude. For magnitude 6―9 earthquakes, the natural period is about 1―6 hours. Such oscillation comes from the epicenter area and they can propagate several thousand kilometers in the Earth's crust. Before a strong earthquake in the shallow crust, the conductive pore fluid will experience major changes before the fault rapture. Such fluid change will emit an oscillation in the pore fluid pressure. This is the mechanism for the HRT wave generation. Since the China Earthquake Administration funded the HRT wave short-term earth-quake prediction project in 2003, the first record of HRT precursor wave has been recorded from the 2004-12-26 Sumatra Mw9.0 earthquake with the largest epicentre distance Δ=2900 km. Thereafter, we have captured HRT waves from more than twenty strong earthquakes, which are well-matched and show repeatability, consistency and regularity. All our observation with the HRT waves demonstrate that HRT wave precursors to earthquakes indeed exist. Strong earthquakes can be predicted and short-term and impending earthquake prediction is achievable in the very near future. From all the observations, including the ones at HG station from Wenchuan Ms8.0 earthquake, we conclude that using HRT wave to predict earthquakes is feasible.展开更多
The Changshu earthquake (M_s = 5.1) occurred at 17:57 (GMT, hereinafter) on Feb. 9, 1990, and it was sensible around Shanghai, Wuxi and some other places. The epicenter was at 31.6°N, 121°E. We predicted on ...The Changshu earthquake (M_s = 5.1) occurred at 17:57 (GMT, hereinafter) on Feb. 9, 1990, and it was sensible around Shanghai, Wuxi and some other places. The epicenter was at 31.6°N, 121°E. We predicted on Feb. 6, 1990 that there would be an earthquake with magnitude 5—6 in the south Huanghai Sea-north Jiangsu Province region, There were a展开更多
In the IAF Congress ’92 a multiple small satellite Earth observation system was put forward with sensors of visible and infrared spectrums. The system could shorten the revisiting period so that any place on the worl...In the IAF Congress ’92 a multiple small satellite Earth observation system was put forward with sensors of visible and infrared spectrums. The system could shorten the revisiting period so that any place on the world could be observed twice a day Now we extend the idea to the microwave remote sensing satellite system. The main purpose of the system is the impending forecast of earthquakes. According to the theory and long-time concrete practice of Qiang Zuji through the observation of temperature increase of the low layer of atmosphere and its moving trend caused by some sorts of radiation and gases released from Earth interior, an impending strong earthquake could be predicted in time. As the temperature increase is detected by thermo-infrared spectrum sensors on the meteorological satellites. the observation may be sometimes obstructed by cloud or rain. In the suggested system, mm-wave radiometers are used and those obstructions could be generally overcome. Besides, radiometers of some other microwave frequencies are also included so as to make the small satellite system useful for observation of atmosphere. soil and crops. The plattorm construction and the altitude control system of the satellites suitable to the sweeping radiometer antennas are stressfully implemented. The orbit of the satellites in the system is well designed so that any place in the world could be observed twice a day in accordance with the optical small satellite system.展开更多
This note mainly discusses the relation of the impending-earthquake satellite thermal infrared anomaly with the ground temperature-increase anomaly, namely, expounds the problem if the satellite thermal infrared anoma...This note mainly discusses the relation of the impending-earthquake satellite thermal infrared anomaly with the ground temperature-increase anomaly, namely, expounds the problem if the satellite thermal infrared anomaly is the reflection of the surficial temperatureincrease anomaly caused by seismic activities on the basis of previous works about the rela-展开更多
People have already recognized the temperature-increase anomaly before earthquakes and studies have been made on this phenomenon. With the method of fixed-point network observation, only the timing temperature data li...People have already recognized the temperature-increase anomaly before earthquakes and studies have been made on this phenomenon. With the method of fixed-point network observation, only the timing temperature data limited to some sites can be obtained instead of dynamic evolution data of the temperature in a large area within the seismogenic range.展开更多
Based on an interpretation and study of the satellite remote-sensing images of FY-2C thermal infrared 1st wave band (10.3-11.3 μm) designed in China, the authors found that there existed obvious and isolated satell...Based on an interpretation and study of the satellite remote-sensing images of FY-2C thermal infrared 1st wave band (10.3-11.3 μm) designed in China, the authors found that there existed obvious and isolated satellite thermal infrared anomalies before the 5.12 Wenchuan Ms 8.0 Earthquake. These anomalies had the following characteristics: (1) The precursor appeared rather early: on March 18, 2008, i.e., 55 days before the earthquake, thermal infrared anomalies began to occur; (2) The anomalies experienced quite many and complex evolutionary stages: the satellite thermal infrared anomalies might be divided into five stages, whose manifestations were somewhat different from each other. The existence of so many anomaly stages was probably observed for the first time in numerous cases of satellite thermal infrared research on earthquakes; (3) Each stage lasted quite a long time, with the longest one spanning 13 days; (4) An evident geothermal anomaly gradient was distributed along the Longmen seismic fracture zone, and such a phenomenon might also be discovered for the first time in satellite thermal infrared earthquake research. This discovery is therefore of great guiding and instructive significance in the study of the earthquake occurrence itself and the trend of the postearthquake phenomena.展开更多
A multi functional high frequency seismometer, a new instrumental system, is used for recording multi point strain variations of rock samples in the process of fracture development. The results indicate that strain...A multi functional high frequency seismometer, a new instrumental system, is used for recording multi point strain variations of rock samples in the process of fracture development. The results indicate that strain in each point appears burst disturbance synchronously besides a tendency variation before main fracture. The burst disturbance could probably be one of the short impending precursors before great earthquake.展开更多
This paper gives a report on borehole bulk-strain data recorded at the seismostation Nanton$ in Jiangsu Province from January 1 , 2003 to December 31 , 2008. While the data at Nantong showed much noise possibly due to...This paper gives a report on borehole bulk-strain data recorded at the seismostation Nanton$ in Jiangsu Province from January 1 , 2003 to December 31 , 2008. While the data at Nantong showed much noise possibly due to site instability and no earthquake-related changes, the data at Liuhe showed anomalous changes that began one to several weeks before three earthquakes of magnitude 4.0 to 6.0 at eplcentral distances up to 400 kin.展开更多
It is attracting more and more attention of seismologists in the world that electromagnetic radiation (EMR) was observed before some strong earthquake occurrence (Takahashi, 1988; Warwick, 1982; Yoshino, 1986 ; Oike,1...It is attracting more and more attention of seismologists in the world that electromagnetic radiation (EMR) was observed before some strong earthquake occurrence (Takahashi, 1988; Warwick, 1982; Yoshino, 1986 ; Oike,1985 ; Fujinawa, 1990 ; Qian. 1992, Zhang, 1992). The international co-operation have promoted the development of this kind of science for getting more data to study SEMR physical mechanism. The observation equipments were provided by Japan, the observation installations were provided by the Seismological Bureau of Yunnan Province. Two observatories were built by Prof. Kozo Takahashi and Yukio Fujinawa, and some Chinese seismologists at Xiao Shao. Kunming, and Yuexi, Dan in Nov. 3~7, 1992. Here, some characters of SEMR in Yunnan Province and prediction efficience of the methods of impending earthquake prediction are obtained. And it was found that before the Pu'er M6. 3 earthquake of 1993, that the occurrence time of EMR signals before strong earthquakes approximately synchronizes some other precursors, for example, of water level, water radon and F-ion. That means the SEMR signals are generated by the activation of the tectonic belt in the seismogenic zone.展开更多
According to studies of more than 20 earthquakes with MS≥5.0 in North China, seven features of the short-term and imminent earthquake precursors have been summarized in this paper. At the same time, taking the short-...According to studies of more than 20 earthquakes with MS≥5.0 in North China, seven features of the short-term and imminent earthquake precursors have been summarized in this paper. At the same time, taking the short-term and imminent earthquake stage as the physical process of a source’s medium softening and fault creep, we calculated temporal variation of mean stress, maximum shear stress, body strain, and pore pressure in some certain points (supposed stations) in the source area and its adjacent area by using an anisotropic and nonlinear source model and a finite element method. According to an analysis of these theoretical curves, we conclude that the short-term and imminent earthquake precursors have such characteristics as complex shapes, exponential growth of the precursor number with tune, and precursors’ migration from the outside area to the source area, which to a certain extent reveal the cause of the characteristics of the short-term and imminent earthquake precursor field.展开更多
To improve acoustic performance of an air cleaner system,both experimental and theoretical studies were carried out.The air cleaner's acoustic numerical model was built by finite element methods(FEM).Acoustic param...To improve acoustic performance of an air cleaner system,both experimental and theoretical studies were carried out.The air cleaner's acoustic numerical model was built by finite element methods(FEM).Acoustic parameters of filter paper imported in the FEM model were calculated according to experiential formulas.Based on the models,the cleaner's acoustic character of transmission loss(TL) was computed.To verify the numerical results,TL results of the real air cleaner with or without filter paper were tested by four-microphone transferring function method.The experimental results show that the filter paper influence acoustic performance of the air cleaner significantly,especially in mid and high frequency band,and should be considered in numerical simulation.Comparisons between experimental and numerical results show that the numerical model is accurate enough to be used in multi-scheme acoustic optimization.Based on our study,TL results of two schemes were calculated and analyzed,which is useful to the air cleaner's final design decision.展开更多
Based on the thermal anomalous temperature increase, we predicted that there would be an earthquake of magnitude 5 to 6 in the eastern and southeastern water areas of Taiwan Island on March 7,1991. The predicted valid...Based on the thermal anomalous temperature increase, we predicted that there would be an earthquake of magnitude 5 to 6 in the eastern and southeastern water areas of Taiwan Island on March 7,1991. The predicted valid period would be from March 7 to March 17, 1991. As expected, there did occur an earthquake of magnitude 6.0 at 27.0°N, 120.3°E, east of Tainan City, Taiwan. In another case, based on the展开更多
Only in the range of abnormal area determined can we analyze the relation of the surface temperature variation at a single station with earthquakes. Namely, we must adopt the combined method of the plan and time-tempe...Only in the range of abnormal area determined can we analyze the relation of the surface temperature variation at a single station with earthquakes. Namely, we must adopt the combined method of the plan and time-temperature curves to study the ground temperatureincrease anomalies. Altogether 15 earthquakes of M】5.0 which occurred in the mainland展开更多
A series of silicates with double shell hollow sphere morphology were prepared by hydrothermal method with ultra-high temperature calcined,and used in the field of electromagnetic(EM)wave absorption.By characterizing ...A series of silicates with double shell hollow sphere morphology were prepared by hydrothermal method with ultra-high temperature calcined,and used in the field of electromagnetic(EM)wave absorption.By characterizing the chemical composition,crystal structure,micro morphology and EM parameters of the several materials,the evaluation results of EM wave absorption capacity of the materials were obtained.In the discussion section,we will discuss the reasons for the differences in EM wave absorption capabilities of the several silicates from multiple aspects such as EM wave absorption mechanism in detail.Especially for iron-based silicate(HGMs@Fe_(2)SiO_(4))materials,after reasonable composition and morphology design,the minimum reflection loss(RLmin)reached up to-41.14 d B with a matching thickness(d)of 3.4 mm,and the corresponding effective absorption bandwidth(f_(E),RL<-10 d B)was 6.80 GHz.Because of the wide EM wave absorption bandwidth,light weight and low water absorption,this kind of double shell silicate material has gained huge application potential in the EM wave absorption field.展开更多
文摘In this paper, the causes of the occurrence of the temperature increase by an impending earthquake of low altitude atmosphere and on the ground surface have been preliminarily expounded through several simulative controlexperiments. Air polarized by the anomalous atmospheric static electric field is regarded as the primary factor tocreate air temperature increase to a large degree and over a large area in the sunlight. In addition, another causeis considered as the temperature increase effect of “polluted” air.
基金the Knowledge Innovation Program of Chinese Academy Sciences (KZX3-SW-352)Frontier Program of Institute of Mountain Hazards and Environment, CAS (C3200307)
文摘Debris flow prediction is one of the important means to reduce the loss caused by debris flow. This paper built a regional prediction model of impending debris flow based on regional environmental background (including topography, geology, land use, and etc.), rainfall and debris flow data. A system of regional prediction of impending debris flow was set up on ArcGIS 9.0 platform according to the model. The system used forecast precipitation data of Doppler weather radar and observational precipitation data as its input data. It could provide a prediction about the possibility of debris flow one to three hours before it happened, and was put into use in Liangshan Meteorological Observatory in Sichuan province in the monsoon of 2006.
基金sponsored by Application of Digital Seismic Technology in Short-and Medium-term Prediction of Strong Earthquakes:a Special Topic of the Twelfth “Five-year Plan” Chinese Science and Technology Support Plan(2012BAK19B02-01)
文摘Based on repeated comparison studies of broadband digital seismic records before the Wenchuan MS8. 0,Yushu MS7. 1 and Qingchuan MS5. 4 earthquakes,the possible microseismic fluctuations before impending earthquakes were preliminarily identified. In order to verify and test this phenomenon,a real-time tracking technical system was established by using continuous waveform records of more than 200 wide-band digital seismic stations in regional networks such as Gansu,Qinghai,Sichuan,Yunnan and Tibet.Through real-time tracking and dynamic monitoring of 24 earthquakes with M≥5. 0 occurring in the Qinghai-Tibetan block during the period of 2012-2014 and the observations of stations in some non-seismic areas,the reproducibility and objectivity of the impending earthquake phenomenon were verified. The main characteristics of the microseismic fluctuation phenomena immediately preceding the strong earthquakes are as follows:(1)the spectrum range is wider,the dominant frequency is 11-16 Hz,and the spectrum shape is more regular;(2)it appears 6-24 days before the earthquake,averaging about 15 days;(3)it is possible to be recorded by the stations within the epicenter distance of 50 km,and the stations with the epicenter distance of more than 50 km generally cannot record it;(4)this phenomenon is directional,i. e. the direction in which the activity degree,N-value,varies significantly may be related to the location of the seismic source,the seismogenic fault and the distribution of aftershocks of the strong earthquake. The preliminary study shows that the impending-earthquakes microseismic phenomena may be related to the pre-activity,micro-vibration and micro-rupture in the source region in the imminent stage,or the microactivity and micro-rupture associated with the active tectonics.
基金Project supported by the State 863 High-Tech Project (Grant No. 863-2-7-4-18).
文摘Mechanism of satellitic thermo-infrared brightness temperature and temperature increasing is studied. Experiments are made with a gas sample taken around the epicenter area. The gas sample is proved to contain green house gases such as CH<sub>4</sub> and CO<sub>2</sub> which have increased by tens of thousands of times. In addition, lab research also proves that CH<sub>4</sub> and CO<sub>2</sub> can obtain energy under the action of transient electric field and release heat, thus resulting in a temperature increase of 2—6℃. Also a brief account of practices since 1990 is given; altogether 40 short-term and impending earthquake predictions have been made, with 9 precise ones whose three main factors of an earthquake are clearly depicted, and 12 fairly good ones. These predictions include 3 earthquakes of M<sub>s</sub>≥7, 4 of M<sub>s</sub>≥6.0 and the rest are around M<sub>s</sub> 5.0. Yet there are earthquakes left out of prediction. Finally the evolutionary processing characters of satellitic thermo-infrared brightness temperature and temperature increase before
文摘We deployed four geo-electric monitoring stations in Sichuan and Yunnan provinces from 2004, using the new generation of equipment (PS-100) and technologies to capture the HRT wave earthquake precursor. Before the Wenchuan Ms8.0 earthquake, we recorded the HRT wave precursor at the only operating station in Hongge (HG, Δ=465 km) and found that significant impending signal had been recorded at the station in the early morning ( 0―5 am) of 12th of May, 2008. The precursor for this earthquake is consistent with precursors recorded for other strong earthquakes. The measured physical properties (geo-resistivity and telluric-current) show tidal wave period oscillations from several days to several months before the earthquakes and the amplitude of such HT oscillation increases significantly towards the occurrence of an earthquake. These HT and RT waves from the epicenter have a causal relationship with the earthquakes that happened several days later. The arrival time of two RT waves is proportional to the distance from the station to the epicenter. The estimated natural decay of the amplitude is correlated with the natural period (T0) of the earthquake fault, which is proportional to the fault length. From this relationship, we can predict the earthquake magnitude. For magnitude 6―9 earthquakes, the natural period is about 1―6 hours. Such oscillation comes from the epicenter area and they can propagate several thousand kilometers in the Earth's crust. Before a strong earthquake in the shallow crust, the conductive pore fluid will experience major changes before the fault rapture. Such fluid change will emit an oscillation in the pore fluid pressure. This is the mechanism for the HRT wave generation. Since the China Earthquake Administration funded the HRT wave short-term earth-quake prediction project in 2003, the first record of HRT precursor wave has been recorded from the 2004-12-26 Sumatra Mw9.0 earthquake with the largest epicentre distance Δ=2900 km. Thereafter, we have captured HRT waves from more than twenty strong earthquakes, which are well-matched and show repeatability, consistency and regularity. All our observation with the HRT waves demonstrate that HRT wave precursors to earthquakes indeed exist. Strong earthquakes can be predicted and short-term and impending earthquake prediction is achievable in the very near future. From all the observations, including the ones at HG station from Wenchuan Ms8.0 earthquake, we conclude that using HRT wave to predict earthquakes is feasible.
文摘The Changshu earthquake (M_s = 5.1) occurred at 17:57 (GMT, hereinafter) on Feb. 9, 1990, and it was sensible around Shanghai, Wuxi and some other places. The epicenter was at 31.6°N, 121°E. We predicted on Feb. 6, 1990 that there would be an earthquake with magnitude 5—6 in the south Huanghai Sea-north Jiangsu Province region, There were a
文摘In the IAF Congress ’92 a multiple small satellite Earth observation system was put forward with sensors of visible and infrared spectrums. The system could shorten the revisiting period so that any place on the world could be observed twice a day Now we extend the idea to the microwave remote sensing satellite system. The main purpose of the system is the impending forecast of earthquakes. According to the theory and long-time concrete practice of Qiang Zuji through the observation of temperature increase of the low layer of atmosphere and its moving trend caused by some sorts of radiation and gases released from Earth interior, an impending strong earthquake could be predicted in time. As the temperature increase is detected by thermo-infrared spectrum sensors on the meteorological satellites. the observation may be sometimes obstructed by cloud or rain. In the suggested system, mm-wave radiometers are used and those obstructions could be generally overcome. Besides, radiometers of some other microwave frequencies are also included so as to make the small satellite system useful for observation of atmosphere. soil and crops. The plattorm construction and the altitude control system of the satellites suitable to the sweeping radiometer antennas are stressfully implemented. The orbit of the satellites in the system is well designed so that any place in the world could be observed twice a day in accordance with the optical small satellite system.
基金Project supported by the Seismoscience Joint Foundation
文摘This note mainly discusses the relation of the impending-earthquake satellite thermal infrared anomaly with the ground temperature-increase anomaly, namely, expounds the problem if the satellite thermal infrared anomaly is the reflection of the surficial temperatureincrease anomaly caused by seismic activities on the basis of previous works about the rela-
文摘People have already recognized the temperature-increase anomaly before earthquakes and studies have been made on this phenomenon. With the method of fixed-point network observation, only the timing temperature data limited to some sites can be obtained instead of dynamic evolution data of the temperature in a large area within the seismogenic range.
基金support from the Key Project of Hainan Province Scientific and Technical Plan(grant No.06701)
文摘Based on an interpretation and study of the satellite remote-sensing images of FY-2C thermal infrared 1st wave band (10.3-11.3 μm) designed in China, the authors found that there existed obvious and isolated satellite thermal infrared anomalies before the 5.12 Wenchuan Ms 8.0 Earthquake. These anomalies had the following characteristics: (1) The precursor appeared rather early: on March 18, 2008, i.e., 55 days before the earthquake, thermal infrared anomalies began to occur; (2) The anomalies experienced quite many and complex evolutionary stages: the satellite thermal infrared anomalies might be divided into five stages, whose manifestations were somewhat different from each other. The existence of so many anomaly stages was probably observed for the first time in numerous cases of satellite thermal infrared research on earthquakes; (3) Each stage lasted quite a long time, with the longest one spanning 13 days; (4) An evident geothermal anomaly gradient was distributed along the Longmen seismic fracture zone, and such a phenomenon might also be discovered for the first time in satellite thermal infrared earthquake research. This discovery is therefore of great guiding and instructive significance in the study of the earthquake occurrence itself and the trend of the postearthquake phenomena.
文摘A multi functional high frequency seismometer, a new instrumental system, is used for recording multi point strain variations of rock samples in the process of fracture development. The results indicate that strain in each point appears burst disturbance synchronously besides a tendency variation before main fracture. The burst disturbance could probably be one of the short impending precursors before great earthquake.
基金supported by the National Natural Science Foundation of China( 40901272)Social Development Projects of Science and Technology Department of Jiangsu Province(BS2006085)
文摘This paper gives a report on borehole bulk-strain data recorded at the seismostation Nanton$ in Jiangsu Province from January 1 , 2003 to December 31 , 2008. While the data at Nantong showed much noise possibly due to site instability and no earthquake-related changes, the data at Liuhe showed anomalous changes that began one to several weeks before three earthquakes of magnitude 4.0 to 6.0 at eplcentral distances up to 400 kin.
文摘It is attracting more and more attention of seismologists in the world that electromagnetic radiation (EMR) was observed before some strong earthquake occurrence (Takahashi, 1988; Warwick, 1982; Yoshino, 1986 ; Oike,1985 ; Fujinawa, 1990 ; Qian. 1992, Zhang, 1992). The international co-operation have promoted the development of this kind of science for getting more data to study SEMR physical mechanism. The observation equipments were provided by Japan, the observation installations were provided by the Seismological Bureau of Yunnan Province. Two observatories were built by Prof. Kozo Takahashi and Yukio Fujinawa, and some Chinese seismologists at Xiao Shao. Kunming, and Yuexi, Dan in Nov. 3~7, 1992. Here, some characters of SEMR in Yunnan Province and prediction efficience of the methods of impending earthquake prediction are obtained. And it was found that before the Pu'er M6. 3 earthquake of 1993, that the occurrence time of EMR signals before strong earthquakes approximately synchronizes some other precursors, for example, of water level, water radon and F-ion. That means the SEMR signals are generated by the activation of the tectonic belt in the seismogenic zone.
文摘According to studies of more than 20 earthquakes with MS≥5.0 in North China, seven features of the short-term and imminent earthquake precursors have been summarized in this paper. At the same time, taking the short-term and imminent earthquake stage as the physical process of a source’s medium softening and fault creep, we calculated temporal variation of mean stress, maximum shear stress, body strain, and pore pressure in some certain points (supposed stations) in the source area and its adjacent area by using an anisotropic and nonlinear source model and a finite element method. According to an analysis of these theoretical curves, we conclude that the short-term and imminent earthquake precursors have such characteristics as complex shapes, exponential growth of the precursor number with tune, and precursors’ migration from the outside area to the source area, which to a certain extent reveal the cause of the characteristics of the short-term and imminent earthquake precursor field.
基金Supported by Ministerial Level Advanced Research Foundation(1030021200706)
文摘To improve acoustic performance of an air cleaner system,both experimental and theoretical studies were carried out.The air cleaner's acoustic numerical model was built by finite element methods(FEM).Acoustic parameters of filter paper imported in the FEM model were calculated according to experiential formulas.Based on the models,the cleaner's acoustic character of transmission loss(TL) was computed.To verify the numerical results,TL results of the real air cleaner with or without filter paper were tested by four-microphone transferring function method.The experimental results show that the filter paper influence acoustic performance of the air cleaner significantly,especially in mid and high frequency band,and should be considered in numerical simulation.Comparisons between experimental and numerical results show that the numerical model is accurate enough to be used in multi-scheme acoustic optimization.Based on our study,TL results of two schemes were calculated and analyzed,which is useful to the air cleaner's final design decision.
基金Key project supported by the Eighth National Five-Year Plan for the Development of Science and Technology.
文摘Based on the thermal anomalous temperature increase, we predicted that there would be an earthquake of magnitude 5 to 6 in the eastern and southeastern water areas of Taiwan Island on March 7,1991. The predicted valid period would be from March 7 to March 17, 1991. As expected, there did occur an earthquake of magnitude 6.0 at 27.0°N, 120.3°E, east of Tainan City, Taiwan. In another case, based on the
基金Project supported by the Seismoscience Joint Foundation
文摘Only in the range of abnormal area determined can we analyze the relation of the surface temperature variation at a single station with earthquakes. Namely, we must adopt the combined method of the plan and time-temperature curves to study the ground temperatureincrease anomalies. Altogether 15 earthquakes of M】5.0 which occurred in the mainland
基金Financial support was provided by the National Science Foundation of China(Grants Nos.51872238 and 21806129)the Fundamental Research Funds for the Central Universities(Nos.3102018zy045 and 3102019AX11)+1 种基金the Natural Science Basic Research Plan in Shaanxi Province of China(Nos.2020JM-118 and 2017JQ5116)the Fund of the State Key Laboratory of Solidification Processing in NPU(No.11972303)。
文摘A series of silicates with double shell hollow sphere morphology were prepared by hydrothermal method with ultra-high temperature calcined,and used in the field of electromagnetic(EM)wave absorption.By characterizing the chemical composition,crystal structure,micro morphology and EM parameters of the several materials,the evaluation results of EM wave absorption capacity of the materials were obtained.In the discussion section,we will discuss the reasons for the differences in EM wave absorption capabilities of the several silicates from multiple aspects such as EM wave absorption mechanism in detail.Especially for iron-based silicate(HGMs@Fe_(2)SiO_(4))materials,after reasonable composition and morphology design,the minimum reflection loss(RLmin)reached up to-41.14 d B with a matching thickness(d)of 3.4 mm,and the corresponding effective absorption bandwidth(f_(E),RL<-10 d B)was 6.80 GHz.Because of the wide EM wave absorption bandwidth,light weight and low water absorption,this kind of double shell silicate material has gained huge application potential in the EM wave absorption field.