Testing the Macroseismic Intensity Attenuation Laws for Vrancea Intermediate Depth Earthquakes

Abstract The macroseismic intensity spatial distribution is an important input for most rapid loss modeling and emergency work. Data from a total of 175 earthquakes (Ms ≥ 5.0) in China from 1966 to 2014 were collected, and the rapid assessment method of macroseismic intensity distribution was studied. First, simple relationships among the epicentral intensity, magnitude, and focal depth were established. A greater amount of database is used in this study than that in a previous work (Fu and Liu in Sci R 4(5): 350-354 (1960), Mei in Chin J Geophys 9(1): 1–18 (1960), and Yan et al. in Sci Chin 11: 1050-1058 (1984)), and the studied earthquakes all occurred in the last 50 years, providing more accurate and uniform parameter information. As the seismic intensity-attenuation relationship is traditionally used to estimate the intensity distribution, the macroseismic intensity-attenuation relationship for mainland China was fitted by the earthquake data collected in this region. The deviation of the intensity assessment by the macroseismic intensity-attenuation relationship was examined for 43 earthquakes (Ms ≥ 6.0). In addition, seismic damage emergency assessment work requires the isoseismal lines to be constantly modified according to the updated information. Therefore, an improved ellipse intensity-attenuation model was proposed in this study, completed by the establishment of a semimajor axis and semiminor axis length matrix. Based on the initial value of the length matrix obtained by the regression of historical data and survey data from the site, the least mean squares (LMS) algorithm is used to revise the length matrix. In the end, the practicability of this method is verified by a case study of the Lijiang 7.0 earthquake.

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TESTING THE MACROSEISMIC INTENSITY ATTENUATION RELATIONSHIPS FOR VRANCEA (ROMANIA) SUBCRUSTAL EARTHQUAKES IN RELATION WITH DAMS SITUATED IN EXTRA-CARPATHIAN AREA

19th SGEM International Multidisciplinary Scientific GeoConference EXPO Proceedings19th, Science and Technologies in Geology, Exploration And Mining ◽

10.5593/sgem2019v/1.4/s02.037 ◽

2019 ◽

Author(s):

Angela Petruta Constantin

Keyword(s):

Macroseismic Intensity ◽

Intensity Attenuation ◽

Attenuation Relationships ◽

Subcrustal Earthquakes

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Macroseismic intensity prediction equations for Vrancea intermediate-depth seismic source

Natural Hazards ◽

10.1007/s11069-015-1944-y ◽

2015 ◽

Vol 79 (3) ◽

pp. 2005-2031 ◽

Cited By ~ 10

Author(s):

Radu Văcăreanu ◽

Mihail Iancovici ◽

Cristian Neagu ◽

Florin Pavel

Keyword(s):

Seismic Source ◽

Macroseismic Intensity ◽

Prediction Equations ◽

Intermediate Depth ◽

Intensity Prediction

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Macroseismic intensity attenuation equations for Central Asia earthquakes

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/929/1/012029 ◽

2021 ◽

Vol 929 (1) ◽

pp. 012029

Author(s):

T U Artikov ◽

R S Ibragimov ◽

T L Ibragimova ◽

M A Mirzaev

Keyword(s):

Seismic Hazard ◽

Central Asia ◽

Seismic Intensity ◽

Macroseismic Intensity ◽

Earthquake Magnitude ◽

Source Depth ◽

Strong Earthquakes ◽

Intensity Attenuation ◽

Hazard Assessments ◽

Macroseismic Survey

Abstract Based on macroseismic survey data for strong earthquakes in Central Asia, the coefficients of attenuation of seismic intensities with distance in the Blake-Shebalin- and Kovesligethy -type equations were refined. A new generalized dependence of macroseismic intensity attenuation on distance, taking into account the depth of the earthquake hypocentre, were obtained. Relations between the minor and major axes of the ellipse approximating real isoseists depending on the shaking strength, source depth and earthquake magnitude were found. With the example of the territory of eastern Uzbekistan, the influence of the choice of the law of seismic intensity attenuation with distance on the obtained seismic hazard assessments is investigated.

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Bayesian analysisof a probability distribution for local intensity attenuation

Annals of Geophysics ◽

10.4401/ag-3356 ◽

2009 ◽

Vol 47 (5) ◽

Author(s):

R. Rotondi ◽

G. Zonno

Keyword(s):

Epicentral Distance ◽

Central Italy ◽

Random Variable ◽

Macroseismic Intensity ◽

Propagation Path ◽

Physical Parameters ◽

Intensity Attenuation ◽

Data Points ◽

Local Intensity ◽

Intensity Decay

Intensity attenuation and its variation as a function of the distance and earthquake size is still a critical issue in evaluating seismic hazard. We present a method that allows us to incorporate additional information from the historical earthquake felt reports in the probability estimation of local intensity attenuation. The approach is based on two ideas: a) standard intensity versus epicentral distance relationships constitute an unnecessary filter between observations and estimates; and b) the intensity decay process is affected by many, scarcely known elements (the physical parameters of the source, propagation path effects, building vulnerability, the semi-qualitative character of macroseismic scales, etc.). Hence intensity decay should be treated as a random variable as is the macroseismic intensity. We assume here that decay, defined on the set {0,1, ..., I0}, follows a binomial distribution with parameters (I0, p); p depends on the distance from the epicenter and is related to the probability of null decay at that distance. According to the Bayesian approach this p parameter is, in turn, a Beta random variable. The observations related to earthquakes with their epicenter outside the area concerned, but belonging to homogeneous zones, are used as prior knowledge of the phenomenon, while the data points of events inside the area are used to update the estimates through the posterior means of the quantities involved. Our methodology is described in detail in an application to the Umbria-Marche area in Central Italy. The data sets examined are the macroseismic intensity database DOM4.1 and the zonation ZS.4, both compiled by the Italian Group for Defence against Earthquakes (GNDT). The method is validated by comparing the observed and the estimated intensity data points of the Camerino (28/07/1799) and of the Colfiorito (26/09/1997) earthquakes.

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Seismic history of Pel la and the 1st century B.C. earthquake

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.16883 ◽

2018 ◽

Vol 40 (3) ◽

pp. 1318

Author(s):

I. Zamba ◽

V. Kouskouna

Keyword(s):

A Priori ◽

Macroseismic Intensity ◽

Return Periods ◽

Northern Greece ◽

Attenuation Relations ◽

Intensity Attenuation ◽

History Of ◽

Seismic Records ◽

Macroseismic Intensities ◽

The Town

Research and evaluation of past and recent seismic records is required in order to obtain an overall picture of the seismic history of a given region. To this aim, important information can be collected through the study of monuments and the damage that they may have experienced during their history. Consequently, the archaeological reports on a hitherto unknown earthquake of the Is' century B.C. in Pella (northern Greece) are particularly interesting. These reports are based on the findings that came to light after the excavations of I.Akamatis in the region where the ancient town of Pella was laying. Beginning with this earthquake, this study tries to reach useful conclusions on the seismicity of Pella, in terms of macroseismic intensities from all earthquakes that have affected the town. For all these events, the intensity attenuation relations were used to calculate the macroseismic intensity in Pella. Although it is known a priori that the area is characterized as a relatively low seismicity area, the picture of its seismic history indicates the existence of damaging earthquakes with relatively large return periods. More specifically, in Pella the maximum observed intensity was found to be 7/8 during its seismic history, indicating the picture of low-to-moderate seismic hazard in the region.

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