The analysis of historical seismograms: an important tool for seismic hazard assessment. Case histories from French and Italian earthquakes

2011 ◽  
Vol 182 (4) ◽  
pp. 367-379 ◽  
Author(s):  
Nicola Alessandro Pino

AbstractSeismic hazard assessment relies on the knowledge of the source characteristics of past earthquakes. Unfortunately, seismic waveform analysis, representing the most powerful tool for the investigation of earthquake source parameters, is only possible for events occurred in the last 100–120 years, i.e., since seismographs with known response function were developed. Nevertheless, during this time significant earthquakes have been recorded by such instruments and today, also thanks to technological progress, these data can be recovered and analysed by means of modern techniques.In this paper, aiming at giving a general sketch of possible analyses and attainable results in historical seismogram studies, I briefly describe the major difficulties in processing the original waveforms and present a review of the results that I obtained from previous seismogram analysis of selected significant historical earthquakes occurred during the first decades of the XXth century, including (A) the December 28, 1908, Messina straits (southern Italy), (B) the June 11, 1909, Lambesc (southern France) – both of which are the strongest ever recorded instrumentally in their respective countries –and (C) the July 13, 1930, Irpinia (southern Italy) events. For these earthquakes, the major achievements are represented by the assessment of the seismic moment (A, B, C), the geometry and kinematics of faulting (B, C), the fault length and an approximate slip distribution (A, C). The source characteristics of the studied events have also been interpreted in the frame of the tectonic environment active in the respective region of interest. In spite of the difficulties inherent to the investigation of old seismic data, these results demonstrate the invaluable and irreplaceable role of historical seismogram analysis in defining the local seismogenic potential and, ultimately, for assessing the seismic hazard. The retrieved information is crucial in areas where important civil engineering works are planned, as in the case of the single-span bridge to be built across the Messina straits and the ITER nuclear fusion power plant to be built in Cadarache, close to the location of the Lambesc event, and in regions characterized by high seismic risk, such as southern Apennines.

2019 ◽  
Vol 90 (6) ◽  
pp. 2262-2275 ◽  
Author(s):  
Gabriel Candia ◽  
Jorge Macedo ◽  
Miguel A. Jaimes ◽  
Carolina Magna‐Verdugo

ABSTRACT A new computational platform for seismic hazard assessment is presented. The platform, named SeismicHazard, allows characterizing the intensity, uncertainty, and likelihood of ground motions from subduction‐zone (shallow interface and intraslab) and crustal‐zone earthquakes, considering site‐specific as well as regional‐based assessments. The platform is developed as an object‐oriented MATLAB graphical user interface, and it features several state‐of‐the‐art capabilities for probabilistic and deterministic (scenario‐based) seismic hazard assessment. The platform integrates the latest developments in performance‐based earthquake engineering for seismic hazard assessment, including seismic zonation models, ground‐motion models (GMMs), ground‐motion correlation structures, and the estimation of design spectra (uniform hazard spectra, classical conditional mean spectrum (CMS) for a unique tectonic setting). In addition to these standard capabilities, the platform supports advanced features, not commonly found in existing seismic hazard codes, such as (a) computation of source parameters from earthquake catalogs, (b) vector‐probabilistic seismic hazard assessment, (c) hazard evaluation based on conditional GMMs and user‐defined GMMs, (d) uncertainty treatment in the median ground motions through continuous GMM distributions, (e) regional shaking fields, and (f) estimation of CMS considering multiple GMMs and multiple tectonic settings. The results from the platform have been validated against accepted and well‐documented benchmark solutions.


2009 ◽  
Vol 47 (2-3) ◽  
Author(s):  
D. Mayer-Rosa ◽  
G. Schwarz-Zanetti

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.


2017 ◽  
Vol 65 (1) ◽  
pp. 243-257 ◽  
Author(s):  
Rodolfo Console ◽  
Anna Nardi ◽  
Roberto Carluccio ◽  
Maura Murru ◽  
Giuseppe Falcone ◽  
...  

2021 ◽  
Vol 73 (2) ◽  
pp. P260221
Author(s):  
Laura Perucca ◽  
Franck A. Audemard M.

Today it is understood that the seismic risk, as well as any type of risk, is proportional to the disastrous combination of the seismic threat and the vulnerability of the exposed systems. Considering that the seismic threat is of natural origin, therefore not modifiable or controllable by man to any extent - unlike other threats that are anthropic or generated by man himself (eg nuclear explosions, seismicity induced by dams or reservoirs of water, etc.) if they are-, risk reduction is achieved both by increasing resilience (a system's own capacity to recover from an adverse event) and by reducing the exposure of potentially exposed systems. However, it should be noted that risk can be better characterized and quantified if the threat is better defined and known, even though it cannot be controlled. That is why the seismic threat needs to be the best bounded, measured and defined, to the extent of the available information, in order to reduce uncertainties to the maximum. It then requires that the seismic activity of the region under study be studied in detail, which also implies identifying and characterizing the generating sources of these earthquakes (seismogenic faults); that is, the geological faults responsible for such seismicity (seismotectonic association; Figure 1). It is customary in seismic hazard studies to study both aspects (source faults and seismicity) in a radius of at least 200 km; distance resulting from the attenuation of seismic energy as it propagates through the medium. So it is understood that the seismic energy released during most large earthquakes is expected to be attenuated to low hazard levels at that distance. The built environment located in sedimentary basins filled with soft or little consolidated sediments, such as the cases of Mexico City and Caracas, probably escape this practice, due to wave amplification effects as a site effect, which could be excited by large shallow or shallow earthquakes. subduction, with epicenters beyond that distance prescribed by practice. Consequently, it is necessary to retrace the seismic history –or earthquake chronology, which is the sum of the instrumental, historical and pre-historical earthquakes that make up the entire seismic activity (Audemard, 2019) - of the region surrounding the site. subject to a seismic hazard assessment (EAS; in English, Seismic hazard Assessment -SHA-), in the most complete way, as well as extensive in the time possible, in order to determine two fundamental parameters when calculating said estimate: the Maximum probable earthquake and the return period of large earthquakes with destructive capacity, for each of the identified faults, or their individual segments if they are defined. Given that these EAS can be addressed by two approaches, probabilistic and deterministic (or various combinations of both), the longest in time is the evaluated period, the statistical evaluations of both parameters indicated above - known under the term of seismogenic potential- , they will be more robust and reliable to estimate the seismic threat.


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