On the estimation of focal depth from macroseismic data*

1938 ◽  
Vol 28 (4) ◽  
pp. 259-261 ◽  
Author(s):  
H. Neuberger
Keyword(s):  
Focal Depth ◽  
Macroseismic Data

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.

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 parameters of historical earthquakes based on macroseismic data

2020 ◽  
Vol 2 (1) ◽  
pp. 62-75
Author(s):  
Vladlen Cardanets
Keyword(s):  
Field Equation ◽  
Focal Depth ◽  
Historical Earthquakes ◽  
Seismic Effect ◽  
Macroseismic Data ◽  
Earthquake Parameters ◽  
Macroseismic Field ◽  
Carpathian Region ◽  
Wide Range ◽  
Determination Of Parameters

The paper attempts to determine the main parameters of historical earthquakes of the Carpathian region based on macroseismic data, using the macroseismic field equation, indirect parameters, and complex comparison with modern earthquakes. So far, the main source of information about the parameters of historical earthquakes in the Carpathian region has been "New catalog of strong earthquakes ...". In this catalog, all parameters are defined very ap-proximately, with a wide range of values. In addition, over the forty-year period since the release of the catalog, the initial macroseismic data of Carpathian region earthquakes have been substantially replenished and re-evaluated using the MSK-64 macroseismic scale. The study determined such basic parameters of historical earthquakes as the macroseismic epicenter, the intensity at the epicenter, focal depth, and magnitude. As well as additional parameters: direction of the maximum macro-seismic effect, area of intensity zones, distance, and azimuth to the extreme point where the earthquake was felt. The earthquake parameters were calculated using the attenuation formula of the macroseismic field with coefficients obtained by the R.Z. Burtiev for intermediate earthquakes of the Vrancea zone of the Carpathian region, separately in four azimuthal ranges. For crustal earthquakes, the general Blake-Shebalin macroseismic field equation was used. Despite possible errors associated with a correct assessment of intensity at observation points, as well as the accuracy of the coefficients of the macro-seismic field equation used for specific seismic events, it was possible to determine the type of each historical earthquake and obtain more accurate values of their parameters. The re-fined parameters of historical earthquakes will allow making a more holistic picture of the seismic hazard in the Carpathian region.

AlCu Pattern Generation on 3D StructuredWafer Using Multi Level Exposure Method on Electrodeposited Polymer Material

2003 ◽  
Vol 766 ◽  
Author(s):  
Vineet Sharma ◽  
Arief B. Suriadi ◽  
Frank Berauer ◽  
Laurie S. Mittelstadt
Keyword(s):  
Line Width ◽  
Metal Film ◽  
Focal Depth ◽  
Cost Effective ◽  
Pattern Generation ◽  
Promising Technique ◽  
Critical Dimensions ◽  
Exposure Method ◽  
Multi Level ◽  
3D Surfaces

AbstractNormal photolithography tools have focal depth limitations and are unable to meet the expectations of high resolution photolithography on highly topographic structures. This paper shows a cost effective and promising technique of combining two different approaches to achieve critical dimensions of traces on slope pattern continuity on highly topographic structures. Electrophoretically deposited photoresist is used on 3-D structured wafers. This photoresist coating technique is fairly known in the MEMS industries to achieve uniform and conformal photoresist films on 3D surfaces. Multi step exposures are used to expose electrophoretically deposited photoresist. AlCu (Cu-0.5%), 0.47-0.53 μm thick metal film is deposited on 3D structured silicon substrate to plate photoresist. By combining these two novel methods, metal (AlCu) traces of 75 μm line width and 150 μm pitch (from top flat to down the slope) have been demonstrated on isotropically etched 350 μm deep trenches with 5-10% line width loss.

scholarly journals Analysis of Predistortion Techniques on Fresnel Zone Plates in Ultrasound Applications

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5066
Author(s):  
José Miguel Fuster ◽  
Sergio Pérez-López ◽  
Francisco Belmar ◽  
Pilar Candelas
Keyword(s):  
Intensity Distribution ◽  
Fresnel Zone ◽  
Focal Depth ◽  
Acoustic Intensity ◽  
Fresnel Zone Plates ◽  
Therapeutic Applications ◽  
Zone Plates ◽  
Ultrasound Applications

In this work, we analyze the effect of predistortion techniques on the focusing profile of Fresnel Zone Plates (FZPs) in ultrasound applications. This novel predistortion method is based on either increasing or decreasing the width of some of the FZP Fresnel rings by a certain amount. We investigate how the magnitude of the predistortion, as well as the number and location of the predistorted rings, influences the lens focusing profile. This focusing profile can be affected in different ways depending on the area of the lens where the predistortion is applied. It is shown that when the inner area of the lens, closer to its center, is predistorted, this technique allows the control of the focal depth at the main focus. However, when the predistortion is applied to an area farther from the center of the lens, the acoustic intensity distribution among the main focus and the closest adjacent secondary foci can be tailored at a certain degree. This predistortion technique shows great potential and can be used to control, modify and shape the FZP focusing profile in both industrial and therapeutic applications.

The 4 December 2015 Mw 7.1 Normal-Faulting Antarctic Plate Earthquake and Its Seismotectonic Implications

2020 ◽  
Vol 110 (3) ◽  
pp. 1090-1100
Author(s):  
Ronia Andrews ◽  
Kusala Rajendran ◽  
N. Purnachandra Rao
Keyword(s):  
Body Wave ◽  
Focal Depth ◽  
Normal Fault ◽  
Normal Faults ◽  
Oceanic Plate ◽  
Normal Faulting ◽  
Transform Faults ◽  
Wave Inversion ◽  
Spreading Ridges ◽  
Southeast Indian Ridge

ABSTRACT Oceanic plate seismicity is generally dominated by normal and strike-slip faulting associated with active spreading ridges and transform faults. Fossil structural fabrics inherited from spreading ridges also host earthquakes. The Indian Oceanic plate, considered quite active seismically, has hosted earthquakes both on its active and fossil fault systems. The 4 December 2015 Mw 7.1 normal-faulting earthquake, located ∼700  km south of the southeast Indian ridge in the southern Indian Ocean, is a rarity due to its location away from the ridge, lack of association with any mapped faults and its focal depth close to the 800°C isotherm. We present results of teleseismic body-wave inversion that suggest that the earthquake occurred on a north-northwest–south-southeast-striking normal fault at a depth of 34 km. The rupture propagated at 2.7  km/s with compact slip over an area of 48×48  km2 around the hypocenter. Our analysis of the background tectonics suggests that our chosen fault plane is in the same direction as the mapped normal faults on the eastern flanks of the Kerguelen plateau. We propose that these buried normal faults, possibly the relics of the ancient rifting might have been reactivated, leading to the 2015 midplate earthquake.

Focal shift and extended focal depth with tunable pupil filter

2008 ◽  
Vol 55 (17) ◽  
pp. 2857-2863 ◽  
Author(s):  
Maojin Yun ◽  
El-Hang Lee
Keyword(s):  
Focal Depth ◽  
Focal Shift

Reply to “Comment on ‘Which Earthquake Accounts Matter?’ by Susan E. Hough and Stacey S. Martin” by David J. Wald

2021 ◽  
Author(s):  
Susan E. Hough ◽  
Stacey S. Martin
Keyword(s):  
Scientific Community ◽  
Recent Article ◽  
Geological Survey ◽  
Data Sets ◽  
Macroseismic Data ◽  
Education Programs ◽  
Socioeconomic Groups ◽  
Science Projects ◽  
Community Science ◽  
The U.S

Abstract We thank David Wald (Wald, 2021; henceforth, W21) for his interest in our recent article (Hough and Martin, 2021; henceforth, HM21). Although different perspectives are vital in science, we are concerned that W21 misrepresents HM21 as an oblique criticism of the U.S. Geological Survey “Did You Feel It?” (DYFI) system, calling for HM21 to be retracted. Readers who are interested in the issues raised by HM21 and the statements made by us therein are referred to that article. In this brief reply, we respond to specific accusations made by W21 and return to the focus of HM21, calling attention to the extent to which macroseismic data sets and inferences drawn from them can be shaped by a lack of representation among individuals whose observations are available to science. HM21 never questioned the benefits of the community science DYFI project to science. HM21 noted, however, and we reiterate here, that community science also potentially benefits the community. Whether or not it matters for science, if participation in community science projects is unrepresentative across socioeconomic groups, it underscores the need for the scientific community to be proactive in its efforts to reach out to groups that have been underserved by current outreach and education programs. We appreciate this opportunity to continue the important conversation about representation.

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