The uncertainties of a Pd3–PGV onsite earthquake early warning system

Earthquake early warning systems have been developed to help minimize the loss of life and other damages resulting from catastrophic earthquakes. In the past several decades, these systems have evolved to function using a variety of methodologies. This study introduces an onsite system developed from a correlation between the precursor measurement (Pd3) and the peak ground acceleration (PGV) from 780 historical earthquake events recorded in Taiwan, Japan and South California. The study analyzes and integrates the uncertainty of the onsite system, establishing the statistical relationship between the PGV forecast, the Pd3 precursor, and the exceedance probability (P_E). A method is presented for forecasting the PGV by scaling the Pd3. Furthermore, this study also suggests a decision-making model to determine whether or not the early warning notification should be issued, based on factors such as the uncertainty of the early warning system, the magnitude of the precursor, and warning recipient characteristics.     

The research on Hainan earthquake insurance system

ＴｈｅｒｅｓｅａｒｃｈｏｎＨａｉｎａｎｅａｒｔｈｑｕａｋｅｉｎｓｕｒａｎｃｅｓｙｓｔｅｍＦＡＮ－ＬＵＡＮＳＨＥＮ１）（沈繁銮），ＺＨＩ－ＸＩＯＮＧＬＩ１）（李志雄），ＤＩＮＧＣＨＥＮ１）（陈定），ＨＡＩ－ＨＵＡＬＩ１）（李海华），ＤＩＮＧ－ＪＩＥＷ...     

A new method for earthquake prediction by earth-resistivity measurements

Ａ　ｎｅｗ　ｍｅｔｈｏｄ　ｆｏｒ　ｅａｒｔｈｑｕａｋｅ　ｐｒｅｄｉｃｔｉｏｎ　ｂｙ　ｅａｒｔｈ－ｒｅｓｉｓｔｉｖｉｔｙ　ｍｅａｓｕｒｅｍｅｎｔｓ（薛顺章）（温新民）（董永德）（梁子彬）（张庆渊）（赵和云）Ａｎｅｗｍｅｔｈｏｄｆｏｒｅａｒｔｈｑｕａｋｅ...     

The Datong earthquake and its anomalous tilt Field

ＴｈｅＤａｔｏｎｇｅａｒｔｈｑｕａｋｅａｎｄｉｔｓａｎｏｍａｌｏｕｓｔｉｌｔｆｉｅｌｄＡｎ－ＦｕＮＩＵ（牛安福）；Ｙｉ－ＬｉｎＷＵ（吴翼麟）；Ｄｅ－ＦｕＣＨＥＮ（陈德福）ａｎｄＸｉａｏ－ＪｕｎＬＩ（李晓军）（ＩｎｓｔｉｔｕｔｅｏｆＳｅｉｓｍｏｌｏｇｙ...     

The 2014–2015 earthquake series in the northern Upper Rhine Graben,Central Europe

Since March 2014, an unusually large amount of earthquakes occur southeast of the city of Darmstadt in the northern Upper Rhine Graben. During the period, until April 2015, we have recorded 356 earthquakes with magnitudes ranging from M_L?=??0.6 to 4.2. We identified two source clusters separated laterally by about 5 km. The hypocentres within these clusters are aligned vertically extending over a depth range from 1 to 8 km with a lateral extent of about 1 to 2 km. Focal mechanisms show left-lateral strike-slip movements; b values are changing with time between b?=?0.6 and b?=?0.9. This is the first time in almost 150 years that such high earthquake rates have been observed in the region. Historical accounts dating back to the nineteenth century report of over 2000 felt earthquakes over a time span from 1869 to 1871. From these, maximum intensities of VII have been estimated. Other seismic activities in the region were reported in the 1970s. The observations of the 2014–2015 earthquake series do not completely match a typical main shock–aftershock sequence or a typical earthquake swarm. Especially the activity at the beginning of the earthquake series may be considered as a mixture of a main shock–aftershock sequence and a short-lasting swarm event. Whether or not the time gap between the current seismic activity, which actually takes place at the same locations as parts of the seismic swarm in 1869–1871, and the seismic activity in the nineteenth century or the seismic activity in the 1970s can be interpreted as a seismic cycle remains unclear.     

A new approach to numerical simulation of source development of earthquake

ＡｎｅｗａｐｐｒｏａｃｈｔｏｎｕｍｅｒｉｃａｌｓｉｍｕｌａｔｉｏｎｏｆｓｏｕｒｃｅｄｅｖｅｌｏｐｍｅｎｔｏｆｅａｒｔｈｑｕａｋｅＣＨＵＮ－ＡＮＴＡＮＧ（唐春安）ＹＵ－ＦＡＮＧＦＵ（傅宇方）ＷＥＮＺＨＡＯ（赵文）ＣｅｎｔｅｒｆｏｒＲｏｃｋｂｕｒｓｔｓ...     

Role of wave–mean flow interaction in sun–climate connections: Historical overview and some new interpretations and results

Quasi-decadal variations in solar irradiance – termed the 11-year solar cycle (SC) – have been linked to variations in a variety of atmospheric circulation features, including the polar vortex, the Brewer–Dobson circulation, and the quasi-biennial oscillation. These features share an underlying commonality: they are all rooted in wave–mean flow interaction. The purpose of this paper is to provide a historical overview of the connection between the SC and wave–mean flow interaction and to propose a more complete theoretical framework for solar modulated wave–mean flow interaction that includes both zonal-mean and zonally asymmetric ozone as intermediaries for communicating variations in solar spectral irradiance to the climate system. We solve a quasi-geostrophic model using the WKB formalism to highlight the physics connecting the SC to planetary wave-drag. Numerical results show the importance of the zonally asymmetric ozone field in mediating the effects of solar variability to the wave-driven circulation in the middle atmosphere.     

The fracture characteristic of the 1989 Datong-Yanggao earthquake sequence

Ｔｈｅｆｒａｃｔｕｒｅｃｈａｒａｃｔｅｒｉｓｔｉｃｏｆｔｈｅ１９８９Ｄａｔｏｎｇ－ＹａｎｇｇａｏｅａｒｔｈｑｕａｋｅｓｅｑｕｅｎｃｅＳｉ－ＣｈａｎｇＺＨＡＮＧ（张四昌），Ｇｕｉ－ＬｉｎｇＤＩＡＯ（刁桂苓）ａｎｄＬｉ－ＭｉｎＹＵ（于利民）（Ｓｅｆｒｍｏ...     

The GIS and analysis of earthquake damage distribution of the 1303 Hongtong M=8 earthquake

Introduction The 1303 Hongtong earthquake is an important earthquake in the eastern China. There is a lot of information in historical documents about the earthquake and many traces destroyed by the earthquake in the southern Shanxi Province. Many scholars have studied the earthquake from dif-ferent aspects, but mainly limited the definitions of the isoseismal and three factors of the earth-quake. Owing to being limited by the analysis technique, many useful damage information of the earthqu…     

Study on correlativity among some seismological prediction indexes related to earthquake frequency or energy

Introduction Study of seismicity indexes and prediction methods is an important aspect of earthquake pre-diction research. In recent years, with more and more seismicity indexes being presented and de-veloped, a question is naturally put forward that which ones among so many seismicity indexes are dependent and which ones are independent when they are used to describe seismicity changes. The author studied the correlativities among several non-linear prediction indexes, such as capacity dimens…     

The initial subevent of the 1994 Northridge, California, earthquake: Is earthquake size predictable?

We examine the initial subevent (ISE) of the M 6.7, 1994 Northridge, California, earthquake in order to discriminate between two end-member rupture initiation models: the preslip and cascade models. Final earthquake size may be predictable from an ISE's seismic signature in the preslip model but not in the cascade model. In the cascade model ISEs are simply small earthquakes that can be described as purely dynamic ruptures. In this model a large earthquake is triggered by smaller earthquakes; there is no size scaling between triggering and triggered events and a variety of stress transfer mechanisms are possible. Alternatively, in the preslip model, a large earthquake nucleates as an aseismically slipping patch in which the patch dimension grows and scales with the earthquake's ultimate size; the byproduct of this loading process is the ISE. In this model, the duration of the ISE signal scales with the ultimate size of the earthquake, suggesting that nucleation and earthquake size are determined by a more predictable, measurable, and organized process. To distinguish between these two end-member models we use short period seismograms recorded by the Southern California Seismic Network. We address questions regarding the similarity in hypocenter locations and focal mechanisms of the ISE and the mainshock. We also compare the ISE's waveform characteristics to those of small earthquakes and to the beginnings of earthquakes with a range of magnitudes. We find that the focal mechanisms of the ISE and mainshock are indistinguishable, and both events may have nucleated on and ruptured the same fault plane. These results satisfy the requirements for both models and thus do not discriminate between them. However, further tests show the ISE's waveform characteristics are similar to those of typical small earthquakes in the vicinity and more importantly, do not scale with the mainshock magnitude. These results are more consistent with the cascade model.     

The numerical simulation of thesource development of the Tangshan earthquake

Ｔｈｅｎｕｍｅｒｉｃａｌｓｉｍｕｌａｔｉｏｎｏｆｔｈｅｓｏｕｒｃｅｄｅｖｅｌ┐ｏｐｍｅｎｔｏｆｔｈｅＴａｎｇｓｈａｎｅａｒｔｈｑｕａｋｅＺＨＩ－ＲＥＮＮＩＵ（牛志仁）ＤＡＮＧ－ＭＩＮＣＨＥＮ（陈党民）ＢＩＮＧ－ＱＩＡＮＬＩ（李炳乾）Ｓｅｉｓｍｏｌｏ...     

Fractional Tajimi–Kanai model for simulating earthquake ground motion

The ground acceleration is usually modeled as a filtered Gaussian process. The most common model is a Tajimi–Kanai (TK) filter that is a viscoelastic Kelvin–Voigt unit (a spring in parallel with a dashpot) carrying a mass excited by a white noise (acceleration at the bedrock). Based upon the observation that every real material exhibits a power law trend in the creep test, in this paper it is proposed the substitution of the purely viscous element in the Kelvin Voigt element with the so called springpot that is an element having an intermediate behavior between purely elastic (spring) and purely viscous (dashpot) behavior ruled by fractional operator. With this choice two main goals are reached: (i) The viscoelastic behavior of the ground may be simply characterized by performing the creep (or the relaxation) test on a specimen of the ground at the given site; (ii) The number of zero crossing of the absolute acceleration at the free field that for the classical TK model is \(\infty \) for a true white noise acceleration, remains finite for the proposed model.     

The shock event of October 6,1597 is a strong deep earthquake

A special earth shock event was recorded at 22 counties of the 7 provinces of eastern China on October 6,1597,and 2 volcanic eruptions and seismic activities were recorded in Sanshui county,Xianjingbeidao,Korea atthat day and the 3rd day. Because of the large range of this shock,low intensity,slow attenuation and no extreme-earthquake area,its epicenter and focus could not be determined on the scientific-technological conditions at thattime,In the Seismological Catalogue of China(GU,1983)published in 1983,its epicenter was determined to be inthe Bo Sea(38.5°N,120.0°E),its magnitude was 7;and it was changed into 7.5 in the later Seismological Cata-     

The seismic energy of Yaoan earthquake sequence estimated by peak velocity

For a long time, a quantitative calculation of energy radiated by seismic waves has been an important problem in the basic study of seismology. Up to now the well-known relationship of lgE=l.5MS+11.8 created by Gutenberg and Richter (1956) has still been a better experiential statistical relation for estimating the energy of seismic waves. Since the creation of seismic dislocation model in the 1960s, seismologists have studied a quantitative calculation of energy radiated by seismic waves. F…     

The environment shear stress field for the 1976 Tangshan earthquake sequence

（陈培善，肖磊，白彤霞，王溪莉）Ｔｈｅｅｎｖｉｒｏｎｍｅｎｔｓｈｅａｒｓｔｒｅｓｓｆｉｅｌｄｆｏｒｔｈｅ１９７６Ｔａｎｇｓｈａｎｅａｒｔｈｑｕａｋｅｓｅｑｕｅｎｃｅ￥Ｐｅｉ－ＳｈａｎＣＨＥＮ；ＬｅｉＸＩＡＯ；Ｔｏｎｇ－ＸｉａＢＡＩａｎｄＸｉ－ＬｉＷＡ...     

Fourier–Hilbert versus Hartley–Hilbert transforms with some geophysical applications

An intimate mathematical relation between Hartley and Hilbert transforms is given here in contrast with the well known Fourier and Hilbert transform relations. It is interesting to note that the Fourier–Hilbert and Hartley–Hilbert transforms while possessing the same magnitude differ in phase by 270°. The inverse Hartley–Hilbert transform returns the original function unlike the Fourier–Hilbert transform which results the negative of the original function. Further, it may be realized that the envelope defined here of the analytic signal in both Fourier–Hilbert and Hartley–Hilbert domains numerically remain the same while differing in polarity. The feasibility of Hartley–Hilbert transform for a straight forward interpretation, total magnetic anomaly due to a thin plate from Tejpur, India and self potential data of the Sulleymonkey anomaly in the Ergani Copper district, Turkey are illustrated in contrast with the Fourier–Hilbert transform. This pair of transforms have innumerable geophysical applications.     

The November 14, 2001 west of Kunlun Mountain Pass earthquake: An earthquake with unsaturated surface wave magnitude

Introduction According to the Rapid Earthquake Information Release of CNDSN (Department of Earth- quake Monitoring and Prediction, China Earthquake Administration, 2002), an earthquake with surface wave magnitude MS=8.1 shook west of Kunlun Mountain Pass (KMP) at the juncture of Xinjiang, Qinghai and Xizang on November 14, 2001. This is the largest and the only MS>8.0 earthquake in Chinese mainland over 50 years since the August 15, 1950 MS=8.6 (MW=8.6) Chayuearthquake in Tibeta…