scholarly journals KICHI-HAMRINSKY-II EARTHQUAKE on April 16, 2013 with КР=12.7, MS=4.5, I0=6 (Central Dagestan)

2019 ◽  
pp. 370-376
Author(s):  
O. Asmanov ◽  
M. Daniyalov ◽  
M. Mirzaliyev ◽  
Kh. Magomedov ◽  
Z. Adilov
Keyword(s):  
Historical Earthquakes ◽  
Macroseismic Data ◽  
Instrumental Data ◽  
Seismic Stations ◽  
Earthquake Area

The instrumental data on the source and macroseismic manifestations of the earthquake that occurred on April 16, 2013, with MS=4.5 in the territory of Dagestan are given. An isoseist map was compiled on the MSK-64 scale based on macroseismic data and data from the network of seismic stations in the Dagestan branch of the GS RAS. The data on historical earthquakes recorded in the Kichi-Gamra earthquake area are given

scholarly journals Do seismologists agree upon epicentre determination from macroseismic data? A survey of ESC Working Group ' Macroseismology'

1996 ◽  
Vol 39 (5) ◽  
Author(s):  
I. Cecic ◽  
R. M. W. Musson ◽  
M. Stucchi
Keyword(s):  
Working Group ◽  
Current Practice ◽  
Historical Earthquakes ◽  
Parameter Determination ◽  
Macroseismic Data ◽  
Practical Application ◽  
High Noise ◽  
Instrumental Data ◽  
Macroseismic Parameters

In contrast to the case of instrumental data, the procedures for epicentral parameter determination (coordinates and I0) from macroseismic data are not very well established. Although there are some "rules", upon which most seismologists agree (centre of the isoseismal of largest degree, and so on), the practical application of, such rules displays many problems. Therefore, it is commonly seismologists' practice to find their own pro cedures and solutions; this is particularly evident in the more complicated cases, Such as offshore epicentres or, as in many cases of historical earthquakes, poor sets of data. One of the major consequences is that parametric catalogues are not homogeneous with respect to macroseismic parameters; moreover, merging catalogues compiled according to different criteria can introduce high noise in any catalogue built in such a way. In order to survey the current practice of epicentre determination from macroseismic data in Europe, a set of cases was distributed to the participants of the first meeting of the ESC WG "Macroseismology". A comparison of the 15 sets of results provided by 16 authors, who gave their own solutions and the explanation., of the adopted procedures is given, showing that in some cases the ideas and results are rather distant.

scholarly journals Seismogenic ancient structures of the central and northern part of the East European platform

2019 ◽  
Vol 489 (4) ◽  
pp. 405-408
Author(s):  
V. V. Adushkin ◽  
I. A. Sanina ◽  
G. N. Ivanchenko ◽  
E. M. Gorbunova ◽  
I. P. Gabsatarova ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Seismic Activity ◽  
East European Platform ◽  
Historical Earthquakes ◽  
Seismic Array ◽  
Small Aperture ◽  
Seismic Stations ◽  
East European

The analysis of the location of the epicenters of earthquakes that occurred in the central and northern part of the East European platform in 2009-2016, recorded by the seismic stations of the GS RAS and the small aperture seismic array of IGD RAS Mikhnevo was performed. The results obtained indirectly indicate the seismic activity of the Riphean structures of the region, disturbing the surface of the basement, and their possible activation at the present time. Available data on historical earthquakes also confirm their relevance to paleorifts. It seems important to take into account the position of the ancient aulacogens in assessing the seismic hazard of the East European platform.

scholarly journals Earthquake on December 12, 2020 in the Anapa zone with Mw=3.8, I0=4-5

2021 ◽  
Vol 3 (2) ◽  
pp. 52-66
Author(s):  
Anastasia Zvereva ◽  
Andrei Klianchin ◽  
Irina Gabsatarova
Keyword(s):  
Focal Mechanism ◽  
Seismic Survey ◽  
Corner Frequency ◽  
Shelf Zone ◽  
Density Level ◽  
Macroseismic Data ◽  
North Caucasus ◽  
Spectral Parameters ◽  
Seismic Stations ◽  
The North

The article presents instrumental and macroseismic data on the earthquake on 12.12.2020 at 14:54 with Mw=3.8, h=30 km. The epicenter and parameters of the earthquake were deter-mined using instrumental data from the network of regional seismic stations in the western zone of the North Caucasus of the EGS RAS. This earthquake occurred in the shelf zone of the Eastern Black Sea coast near the resort town of Anapa, in the Anapa seismically active area. This area tectonically is the conjunction of the northern side of the Tuapse trough and the thrust front of the Greater Caucasus. The focal mechanism for the earthquake was calcu-lated. The solution of the focal mechanism was obtained from the polarization in P-waves at 29 seismic stations. From the focal follows the type of source up thrust-thrust movement. The GS RAS organized a macroseismic survey in the Anapa and Novorossiysk regions on the “VKontakte” social network a day after the earthquake. According to the results of the study, 144 respondents in 15 settlements in 7 days were interviewing. The maximum observed in-tensity was I=4-5 points in Su-Psekh and Varvarovka according to the results of the macro-seismic survey, a map of the distribution of intensity points was create. The SEISAN software package calculated the spectral parameters of the source: seismic moment, corner frequency, spectral density level and spectral magnitude Mw.

scholarly journals On historical earthquakes in Switzerland: summary of compilations and investigations

2009 ◽  
Vol 47 (2-3) ◽  
Author(s):  
D. Mayer-Rosa ◽  
G. Schwarz-Zanetti
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Historical Earthquakes ◽  
Macroseismic Data ◽  
The Creation ◽  
Systematic Collection ◽  
Made In

Studies of historical earthquakes in Switzerland are contained in monographs, chronological collections of effects and parametric catalogues. The systematic collection of macroseismic material started with the creation of the Swiss Seismological Commission in 1878. All parametric catalogues since 1975 have been prepared for seismic hazard assessment. The most up-to-date investigation of macroseismic data and compilation into a catalogue (ECOS) was made in the 2002 in context of the re-assessment of seismic hazard for nuclear sites.

scholarly journals About Macroseismic Displays of Yandary Earthquake, October 17, 2018

2019 ◽  
Author(s):  
И.Ю. Дмитриева ◽  
А.А. Саяпина ◽  
С.В. Горожанцев ◽  
С.С. Багаева
Keyword(s):  
Geological Structure ◽  
Point Of View ◽  
Reverse Fault ◽  
Macroseismic Data ◽  
Instrumental Data ◽  
History Of ◽  
The Republic ◽  
October 17 ◽  
The Village ◽  
Focal Zone

В рассматриваемой статье проведен анализ и представлены данные о землетрясении 17 октября 2018 г. в 15h55m по Гринвичу с интенсивностью сотрясений в эпицентре 5 баллов, произошедшего на окраине села Яндаре Республики Ингушетия. По инструментальным данным сетей сейсмических станций NOGSR, OBGSR, DAGSR получено следующее решение параметров землетрясения: 43,27N, 44,92E, h12 км, КР11,5. Приведены сведения по истории сейсмичности очаговой зоны исследуемого землетрясения за последние 150 лет. Очаг землетрясения приурочен к активному Сунженскому разлому. Рассмотрены форшоковая активность и немногочисленная серия афтершоков. Для землетрясения был рассчитан механизм очага по знакам первых вступлений продольных Pволн на 48 станциях, хорошо окружавших эпицентр и расположенных на расстояниях 0,3 50,5 км. Согласно полученному решению землетрясение возникло под действием преобладающих сжимающих напряжений. Тип подвижки в очаге соответствовал взбросу с правосторонним сдвигом по плоскости NP2 с юговосточным простиранием и левостороннему сдвигу с компонентами взброса по плоскости NP1 с субширотным простиранием. Для сбора макросейсмических данных сотрудниками СевероОсетинского филиала ФИЦ ЕГС РАН был осуществлен выезд в эпицентральную зону и близлежащие районы. Оценка интенсивности проводилась на основе шкалы ШСИ 17. Землетрясение с интенсивностью 5 баллов проявилось в населенных пунктах Яндаре, Троицкое, Карабулак. Колебания ощущались в Сунже, Барсуках и Плиево силой 4 балла, Назрани 34 балла. В населенных пунктах Магас, АлиЮрт, Средние Ачалуки ощутимость землетрясения составила 3 балла. В семи населенных пунктах колебания проявились интенсивностью в 2 балла. Во Владикавказе землетрясение ощущалось на верхних этажах многоэтажных зданий. Данные о проявлениях Яндарского землетрясения интересны с точки зрения анализа распределения интенсивности сотрясений, изучения сейсмичности региона в целом, а также связи с геологическим строением территории The article analyzes and presents the data on the earthquake on October 17 at 15h55m GMT, which occurred on the outskirts of the village of Yandare of the Republic of Ingushetia. Intensity of the shok equaled 5 in the epicenter. According to instrumental data of networks of seismic stations NOGSR, OBGSR, DAGSR the following solution of parameters of an earthquake is received: 43,27N, 44,92E, h12 km, KР11,5. The history of seismicity of the focal zone of the investigated earthquake for the last 150 years is studied. The earthquake is confined to the active Sunzha fault. The forshock activity and a few series of aftershocks are considered. For the earthquake, the mechanism of the focus was calculated according to the signs of the first arrivals of longitudinal Pwaves at 48 stations well surrounding the epicenter and located at distances 0,3 50,5 km. According to the received decision, the earthquake appeared under the influence of prevailing compression stresses, the type of movement the reverse fault. For collecting macroseismic data departure in an epicentralny zone and nearby areas was carried out. Evaluation of intensity was carried out on the basis of theSeismic intensity scale (SHSI17). The earthquake with an intensity of 5 points was manifested in the settlements of Yandare, Troitskoye, Karabulak. Fluctuations were felt in Sunzha, Barsuki and Plievo force 4 points, Nazran 34 points. In the settlements of Magas, AliYurt, Middle Achaluki, the sensitivity of the earthquake was 3 points. In seven settlements, the fluctuations showed an intensity of 2 points. In Vladikavkaz earthquake was felt on the upper floors of multistorey buildings. Data on the manifestations of the Yandaryearthquake are interesting from the point of view of the analysis of the distribution of the intensity of concussions, the study of the seismicity of the region as a whole, as well as the connection with the geological structure of the territory.

Using Aftershocks to Help Locate Historical Earthquakes

2020 ◽  
Vol 91 (5) ◽  
pp. 2695-2703 ◽  
Author(s):  
John E. Ebel
Keyword(s):  
Historical Earthquakes ◽  
Seismic Intensity ◽  
Soil Conditions ◽  
Macroseismic Data ◽  
Aftershock Activity ◽  
Earthquake Locations ◽  
Local Soil ◽  
Macroseismic Intensities ◽  
Historical Accounts ◽  
Directivity Effects

Abstract For historical earthquakes, the spatial distributions of macroseismic intensity reports are commonly used to estimate the event locations. The methods to locate historical earthquakes assume that the highest seismic intensity shows the best estimate of the location of the earthquake. Uncertainties in the locations estimated from macroseismic data can be due to an uneven geographic distribution of sites with intensity reports, variations in intensities due to local soil conditions, ambiguous historical reports, and earthquake directivity effects. Additional constraint on the location of a historical earthquake can come from places where most aftershocks were felt, because these localities may have been closest to the fault on which the mainshock took place. Examples of estimated earthquake locations based on aftershocks are those of the 1727 MLg 5.6 earthquake in northeastern Massachusetts, the MLg 5.7 earthquake in Maine, and the 1755 MLg 6.2 earthquake offshore of Cape Ann, Massachusetts. In all of these cases, the earthquake locations based on the aftershock data are somewhat different from previous locations derived from the macroseismic intensities alone. Uncertainties with this method include identifying aftershocks in historical accounts and the possibility that smaller events that are reported following a strong earthquake are not on or near the mainshock rupture. Even so, evidence of possible aftershock activity may help constrain the location of that mainshock. Because aftershocks of strong earthquakes (M≥7) can last months to years, archival research for aftershocks must be carried out with a somewhat different mindset than that for a mainshock.

scholarly journals Moment tensor inversion of early instrumental data: application to the 1917 High Tiber Valley, Monterchi earthquake

2016 ◽  
Vol 59 (3) ◽  
Author(s):  
Fabrizio Bernardi ◽  
Maria Grazia Ciaccio ◽  
Barbara Palombo ◽  
Graziano Ferrari
Keyword(s):  
Focal Mechanism ◽  
Moment Tensor ◽  
Source Parameters ◽  
Normal Fault ◽  
Historical Earthquakes ◽  
Moment Magnitude ◽  
Macroseismic Data ◽  
Natural Period ◽  
Amplitude Spectra ◽  
Tiber Valley

<p>In this paper we present a new study on the High Tiber Valley earthquake occurred on April 26, 1917. Using the digitized data from mechanical seismograph records, we computed the source parameters like focal mechanism and moment magnitude from moment tensor (MT). The study of historical earthquakes from an instrumental perspective is crucial because of the complexity of problems associated with the study of seismograms of moderate to large earthquakes occurred from the late 19th century until the early 1960s. Since historical earthquake records show significant uncertainties in phase arrival times and have been recorded by seismograph generally with short natural period, we developed a code to compute the MT based on a forward modeling technique, which uses the amplitude spectra of the full waveform length and the first P-arrival polarities to constrain the P- and T-axes. The best solution is determined by the best fit between the observed and synthetic amplitude spectra and from the coherency between the observed and the theoretical first P-arrival polarities. The 1917 High Tiber Valley earthquake is one of the most important 20th century earthquake occurred in the Italian Peninsula for which the focal mechanism and moment magnitude from seismic records are not available. Additionally, we apply a multidisciplinary approach to characterize the source of this earthquake, combining instrumental, macroseismic, geological and tectonic data and investigations. The computed MT results in a north-south normal fault mechanism (strike: 147°, dip: 29°, slip: −94°), which is consistent with the strike estimated from the macroseismic data (157°). The moment magnitude calculated from the MT and that derived from the macroseismic data are M<span><sub>w</sub></span>=5.5±0.2 and M<span><sub>w</sub></span>=5.9±0.1, respectively.</p>

A case of the influence of radiation pattern on peak accelerations

1994 ◽  
Vol 84 (5) ◽  
pp. 1658-1664
Author(s):  
Livio Sirovich
Keyword(s):  
Radiation Pattern ◽  
Site Effects ◽  
Strong Motion ◽  
Historical Earthquakes ◽  
Macroseismic Data ◽  
Azimuthal Distribution ◽  
Local Site Effects ◽  
Ground Shaking ◽  
Local Site ◽  
Isoseismal Lines

Abstract The strong ground shaking of the 23 November 1980 earthquake in southern Italy seems to have been conditioned by the dimension of the source, its focal mechanism, and by the distance from the shallow portion of the source. There was only a low, and doubtful, directivity effect. These results come from a comparison of the azimuthal distribution of the recorded peak ground horizontal accelerations with that of the total, dimensionless, radiation pattern of S waves in the horizontal plane at each site (radiation from the closest point of the fault, and appropriate azimuth and take-off angles were considered). The recorded maxima were obtained from hodogram plots of each couple of automatically digitized horizontal components in 13 stations with negligible local site effects at a distance of up to 78 km from the epicenter. The analysis indicates the strong influence of the strike-slip component on the azimuthal distribution of motion. The fault mechanism best fitting the recorded maxima is as follows: strike 318°, dip 64°, rake 317°. This picture does not change if acceleration maxima in the frequency bands 0.1 to 5 Hz, 1 to 5 Hz, or 1 to 2 Hz are used. In a segment of the southern Apennines, where the strong-motion energy radiation in the near/intermediate field of a repetitive series of shocks from the seventeenth century up to 1980 seems to be controlled by the gross features of the source, it could be useful to include radiation patterns into algorithms for regional seismic hazard calculations. Conversely, because of the fact that drawing isoseismal lines results in a smoothing of at least the very local site effects, it might be possible to infer information about the gross features of the sources of historical earthquakes from macroseismic data.

scholarly journals Intensity assignments from historical earthquake data: issues of certainty and quality

1998 ◽  
Vol 41 (1) ◽  
Author(s):  
R. M. W. Musson
Keyword(s):  
Seismic Hazard Assessment ◽  
Historical Earthquakes ◽  
Original Data ◽  
Macroseismic Data ◽  
Historical Earthquake ◽  
Binary Variable ◽  
Intensity Assessment ◽  
Types Of Information ◽  
Expression Of Uncertainty

The use of macroseismic data in assessing parameters for historical earthquakes for use in seismic hazard assessment has thrown more attention on the way in which these data are treated. The processes involved in selecting which macroseismic data from a historical earthquake survive to the present day can be modelled as a series of filters, most of which are outside the control of the seismologist/historian, and which cause distortion in the resulting picture of the earthquake. The ways in which the data become distorted should be taken into account when interpreting the data as intensity values. One can usefully discriminate between the certainty of an intensity assignment (how well the data fits the scale) and the quality of an intensity assignment (how well one can trust that the value is a true reflection of what really happened). The expression of uncertainty is usually in the form of ranged intensity values; the expression of quality requires an extra symbol or rating of some sort. A system is presented for three types of quality problems: reliability of intensity assessment, locational certainty or uncertainty, and veracity of the original data. Each of these is treated as a binary variable, giving a final quality code ranging from 0 (best) to 7 (worst). This single integer quality code preserves three types of information which can then be expanded as required by computer programs designed to handle macroseismic data.

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