Determination of focal depth from macroseismic data

1967 ◽  
Vol 67 (1) ◽  
pp. 107-111 ◽  
Author(s):  
L. Egyed ◽  
A. Mesk�
Keyword(s):  
Focal Depth ◽  
Macroseismic Data

scholarly journals Determination of focal depth by two waveformbased methods: A case study for the 2008 Panzhihua earthquake

2011 ◽  
Vol 24 (4) ◽  
pp. 321-328 ◽  
Author(s):  
Zhenjie Wang ◽  
Jiajun Chong ◽  
Sidao Ni ◽  
Barbara Romanowicz
Keyword(s):  
Focal Depth

scholarly journals SENSIBLE EARTHQUAKES 2013 in MOLDOVA: August 11 with КР=11.8, October 6 with КР=14.1, October 15 with КР=12.3 (Romania–Moldova)

2019 ◽  
pp. 435-444 ◽  
Author(s):  
N. Stepanenco ◽  
N. Simonova ◽  
V. Cardanet
Keyword(s):  
Focal Depth ◽  
Macroseismic Data ◽  
The North ◽  
Crustal Earthquakes ◽  
Carpathian Region ◽  
The Republic ◽  
Regional Solutions ◽  
Weak Shocks ◽  
Significant Spread ◽  
Focal Zone

The article presents instrumental and macroseismic data on earthquakes of the Carpathian region in 2013, felt on the territory of the Republic of Moldova. Three earthquakes, with an intermediate focal depth, occurred in the Vrancea zone: August 11 with h=93 km, КР=11.8; October 6 with h=140 km, КР=14.1; Octo-ber 15 with h=144 km, КР=12.3. Also in 2013, a swarm of small earthquakes was recorded, near Galati (Ro-mania) and Giurgiulesti (Moldova). The swarm arose September 23, its shocks were recorded for two months. More than 370 seismic events happened, of which three had КР  11 (September 29, 30, and Octo-ber 4 with КР=11.2, 10.9, 10.6). The intensity of shaking reached 5. For earthquakes, September 29, 30 and October 4 regional solutions for the focal mechanism from the Mostryukov and Petrov catalog (GO "Borok" IPE RAS) were received. The event of August 11, 2013, with КР=11.8, occurred at a depth of 93 km on the northeastern margin of the focal zone of Vrancea, felt at the epicenter with intensity I=4. In Chisinau, only some people felt weak shocks (I=2). The two largest earthquakes of 2013 occurred on October 6 at 01h 37m (КР=14.2, mb=5.3, I0=6) and on October 15 at 19h 33m (КР=12.3, mb=4.8), in the central part of the focal zone Vrancea. Between these events, three more earthquakes were noted with ML=3–3.5. However, the most extensive macroseismic manifestations arose from the main shock – October 6, which caused shaking in the territory of four states – in Romania, in the north of Bulgaria, in the south-west of Ukraine, and in Moldova. The reason for such a significant spread of tremors lies in a large focal depth of 140 km. But for the same reason, the intensity of the macroseismic impact did not exceed I=5 in Romania and I=4–5 in Moldova and Ukraine. As a result, a map of the intensity distribution of the October 6 earthquake is given, built on the basis of data processing in 104 locations. Various solutions for the focal mechanisms of intermediate earthquakes in 2013 are presented. The consistent manifestation of a swarm of crustal earthquakes and a number of earthquakes of intermediate depth confirms the unity of tectonic processes in the Carpathian region. The accumulated seismic stresses were preliminarily realized in the form of crustal shocks, then powerful discharge occurred in the Vrancea region, which interrupted a series of events associated with Sfintul-Gheorghe and Peceneaga–Camena faults.

On the estimation of focal depth from macroseismic data*

1941 ◽  
Vol 31 (3) ◽  
pp. 225-231 ◽  
Author(s):  
Archie Blake
Keyword(s):  
Absorption Coefficient ◽  
Focal Depth ◽  
Macroseismic Data ◽  
Earthquake Focus ◽  
Precise Form ◽  
Deep Earthquakes ◽  
Satisfactory Method ◽  
Epicentral Intensity

Abstract It has long been known that deep earthquakes are felt more widely, for a given epicentral intensity, than shallow. Several attempts have been made to express this tendency in precise form for the estimation of focal depth. The purpose of this paper is to discuss the shortcomings of the formulas that have been tried and certain ways in which they may be improved. It is noteworthy that while the inverse square of the distance of the observer from the earthquake focus is insufficient to account for the falling off of the intensity, the introduction of an absorption coefficient is not a satisfactory method of dealing with the lack.

scholarly journals Problems of reliability in earthquake parameters determination from historicaI records

1996 ◽  
Vol 39 (5) ◽  
Author(s):  
V. Castelli ◽  
G. Monachesi
Keyword(s):  
Central Italy ◽  
Macroseismic Data ◽  
Earthquake Parameters ◽  
Recent Earthquakes

Earthquake parameters determination from macroseismic data is a procedure, the reliability of whose results can be impaired by many problems related to quality, number and distribution of data. Such problems are common with ancient, sketchily documented events, but can affect even comparatively recent earthquakes. This paper presents some cases of Central Italy earthquakes, the determination of whose epicentral parameters involved problems of reliability. Not all problems can ever be completely solved. It is therefore necessary to devise ways for putting on record the uncertainty of the resulting parameters, so that future users can be aware of them.

The determination of earthquake location and magnitude from macroseismic data in Europe

2014 ◽  
Vol 13 (5) ◽  
pp. 1249-1280 ◽  
Author(s):  
A. A. Gomez-Capera ◽  
A. Rovida ◽  
P. Gasperini ◽  
M. Stucchi ◽  
D. Viganò
Keyword(s):  
Earthquake Location ◽  
Macroseismic Data
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