The Canadian National Seismograph Network: Upgrade and Status

2019 ◽  
Vol 91 (2A) ◽  
pp. 585-592 ◽  
Author(s):  
Allison L. Bent ◽  
Timothy J. Côté ◽  
Henry C. J. Seywerd ◽  
David A. McCormack ◽  
Kathryn A. Coyle

Abstract The Canadian National Seismograph Network (CNSN) operated by Natural Resources Canada consists of approximately 200 stations. Data from this network are used to produce the national earthquake catalog, to provide alerts in the aftermath of an earthquake, to develop the national seismic hazard maps, and for research within Canada and internationally. A significant upgrade to the instrumentation and infrastructure of the CNSN, which began in 2014, is nearing completion. The newly refurbished network is uniform in terms of instrumentation with the remaining single-component short-period stations converted to three-component broadband stations and consistent sampling rates across the network. Strong-motion instruments are now collocated with weak-motion instruments at many sites in all regions of Canada, and there is also a significant increase in the number of stand-alone strong-motion sites. Improvements in telecommunications were aimed at improving reliability and decreasing latency. All upgraded stations undergo a series of quality checks before the data are approved for dissemination. Data from the CNSN are freely available to the seismological community and the general public.

2021 ◽  
Author(s):  
Enrico Brandmayr ◽  
Franco Vaccari ◽  
Giuliano Francesco Panza

AbstractThe Corsica-Sardinia lithospheric block is commonly considered as a region of very low seismicity and the scarce reported seismicity for the area has till now precluded the reliable assessment of its seismic hazard. The time-honored assumption has been recently questioned and the historical seismicity of Sardinia has been reevaluated. Even more, several seismogenic nodes capable of M5 + have been recognized in the Corsica-Sardinia block exploiting the morphostructural zonation technique, calibrated to earlier results obtained for the Iberian peninsula, which has structural lithospheric affinities with the Corsica-Sardinia block. All this allows now for the computation of reliable earthquake hazard maps at bedrock conditions exploiting the power of Neo Deterministic Seismic Hazard Assessment (NDSHA) evaluation. NDSHA relies upon the fundamental physics of wave generation and propagation in complex geologic structures and generates realistic time series from which several earthquake ground motion parameters can be readily extracted. NDSHA exploits in an optimized way all the available knowledge about lithospheric mechanical parameters, seismic history, seismogenic zones and nodes. In accordance with continuum mechanics, the tensor nature of earthquake ground motion is preserved computing realistic signals using structural models obtained by tomographic inversion and earthquake source information readily available in literature. The way to this approach has been open by studies focused on continental Italy and Sicily, where the agreement between hazard maps obtained using seismogenic zones, informed by earthquake catalog data, and the maps obtained using only seismogenic nodes are very good.


2020 ◽  
Author(s):  
Roman Racine ◽  
Carlo Cauzzi ◽  
John Clinton ◽  
Donat Fäh ◽  
Benjamin Edwards ◽  
...  

<p>The Swiss Seismological Service (SED; http://www.seismo.ethz.ch) at ETH Zürich is the federal agency in charge of monitoring earthquakes in Switzerland and neighboring areas, and for the assessment of seismic hazard and risk for the region. The SED seismic network largely relies on software and databases integrated in the SeisComP3 monitoring suite for waveform acquisition, automatic and manual event processing, event alerting, web infrastructure, data archiving and dissemination. Data from all digital seismic stations acquired by the SED over the last 30 years - broadband (presently ~230), strong-motion (~185), short-period (~65), permanent and temporary - are homogeneously integrated in the seismic network processing tools and products. Waveform data from the Swiss National Seismic Networks are openly available through the SED website and ORFEUS EIDA / Strong-Motion (http://orfeus-eu.org/data/) data gateways. The SED earthquake catalogue is publicly available through FDSN Event web services at  the SED (http://arclink.ethz.ch/fdsnws/event/1/). The Swiss seismic hazard maps are integrated in the EFEHR portal (http://www.efehr.org). The SED is updating its strategy for magnitude determination to make it fully consistent with the state-of-the-art in engineering seismology and seismic hazard studies in Switzerland, and to optimise the use of its dense seismic monitoring infrastructure. Among the planned changes are the: (a) adoption of a new ML relationship applicable in the near-source region at epicentral distances smaller than 15-20 km; (b) inclusion of ML station corrections based on empirically observed (de)amplification with respect to the Swiss reference rock velocity model and associated predictions; (c)  seamless computation of Mw based on spectral fitting of recorded FAS using a Swiss specific model. In this contribution we present and discuss the updated magnitude computations for a playback dataset of thousands of recorded earthquakes, and compare them with the current official estimates. We discuss the expected impacts of the new magnitude determination strategy on the SED event processing chain in SeisComP3, the SED catalogues and other seismological products. We welcome community feedback on our planned transition strategy.</p>


2013 ◽  
Vol 8 (5) ◽  
pp. 848-860 ◽  
Author(s):  
Hiroyuki Fujiwara ◽  
◽  
Nobuyuki Morikawa ◽  
Toshihiko Okumura ◽  

Under the guidance of the Headquarters for Earthquake Research Promotion of Japan, we have been carrying out seismic hazard assessment for Japan since the 1995 Hyogo-ken Nanbu Earthquake and have made the National Seismic Hazard Maps for Japan to estimate strong motion caused by earthquakes that could occur in Japan in the future, and show estimated results on these maps. The Hazard Maps consist of two kinds of maps. One kind is a probabilistic seismic hazard map that shows the relation between seismic intensity value and its probability of exceedance within a certain period. The other kind is a scenario earthquake shaking map. In order to promote the use of the National Seismic Hazard Maps, we have developed an open Web system to provide information interactively, and have named this system the Japan Seismic Hazard Information Station (J-SHIS). The 2011 Tohoku Earthquake (Mw9.0) was the largest such event in the recorded history of Japan. This megathrust earthquake was not considered in the National Seismic Hazard Maps for Japan. Based on lessons learned from this earthquake disaster and on experience we have had in the seismic hazardmapping project of Japan, we consider problems and issues to be resolved for seismic hazard assessment and make proposals to improve seismic hazard assessment for Japan.


2020 ◽  
Vol 36 (1_suppl) ◽  
pp. 112-136
Author(s):  
Masyhur Irsyam ◽  
Phil R Cummins ◽  
M Asrurifak ◽  
Lutfi Faizal ◽  
Danny Hilman Natawidjaja ◽  
...  

Indonesia is one of the most seismically active countries in the world, and its large, vulnerable population makes reliable seismic hazard assessment an urgent priority. In 2016, the Indonesian Ministry of Public Works and Housing established a team of earthquake scientists and engineers tasked with improving the input data available for revising the national seismic hazard map. They compiled results of recent active fault studies using geological, geophysical, and geodetic observations, as well as a new comprehensive earthquake catalog including hypocenters relocated in a three-dimensional velocity model. Seismic hazard analysis was undertaken using recently developed ground motion prediction equations (GMPEs), and logic trees for the inclusion of epistemic uncertainty associated with different choices for GMPEs and earthquake recurrence models. The new seismic hazard maps establish the importance of active faults and intraslab seismicity, as well as the subduction megathrust, in determining the level of seismic hazard, especially in onshore, populated areas. The new Indonesian hazard maps will be used to update national standards for design of earthquake-resilient buildings and infrastructure.


2019 ◽  
Vol 41 (4) ◽  
pp. 321-338
Author(s):  
Pham The Truyen ◽  
Nguyen Hong Phuong

In this study, the methodology of probabilistic seismic hazard assessment proposed by Cornell and Esteva in 1968 was applied for Hanoi city, using an earthquake catalog updated until 2018 and a comprehensive seismotectonic model of the territory of Vietnam and adjacent sea areas. Statistical methods were applied for declustering the earthquake catalog, then the maximum likelihood method was used to estimate the parameters of the Gutenberg–Richter Law and the maximum magnitude for each seismic source zone. Two GMPEs proposed by Campbell & Bozorgnia (2008) and Akkar et al., (2014) were selected for use in hazard analysis. Results of PSHA for Hanoi city are presented in the form of probabilistic seismic hazard maps, depicting peak horizontal ground acceleration (PGA) as well as 5-hertz (0.2 sec period) and 1-hertz (1.0 sec. period) spectral accelerations (SA) with 5-percent damping on a uniform firm rock site condition, with 10%, 5%, 2% and 0,5% probability of exceedance in 50 years, corresponding to return times of 475; 975; 2,475 and 9,975 years, respectively. The results of PSHA show that, for the whole territory of Hanoi city, for all four return periods, the predicted PGA values correspond to the intensity of VII to IX degrees according to the MSK-64 scale. As for the SA maps, for all four return periods, the predicted SA values at 1.0 s period correspond to the intensity of VI to VII, while the predicted SA values at 0.2 s period correspond to the intensity of VIII to X according to the MSK-64 scale. This is the last updated version of the probabilistic seismic hazard maps of Hanoi city. The 2019 probabilistic seismic hazard maps of Hanoi city display earthquake ground motions for various probability levels and can be applied in seismic provisions of building codes, insurance rate structures, risk assessments, and other public policy.


Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 101
Author(s):  
Antonio J. Mendoza-Fernández ◽  
Araceli Peña-Fernández ◽  
Luis Molina ◽  
Pedro A. Aguilera

Campo de Dalías, located in southeastern Spain, is the greatest European exponent of greenhouse agriculture. The development of this type of agriculture has led to an exponential economic development of one of the poorest areas of Spain, in a short period of time. Simultaneously, it has brought about a serious alteration of natural resources. This article will study the temporal evolution of changes in land use, and the exploitation of groundwater. Likewise, this study will delve into the technological development in greenhouses (irrigation techniques, new water resources, greenhouse structures or improvement in cultivation techniques) seeking a sustainable intensification of agriculture under plastic. This sustainable intensification also implies the conservation of existing natural areas.


2009 ◽  
Vol 99 (2A) ◽  
pp. 585-610 ◽  
Author(s):  
A. Akinci ◽  
F. Galadini ◽  
D. Pantosti ◽  
M. Petersen ◽  
L. Malagnini ◽  
...  

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