Seismogenic nodes as a viable alternative to seismogenic zones and observed seismicity for the definition of seismic hazard at regional scale

Rugarli, Paolo; Vaccari, Franco; Panza, G. F.

doi:10.15625/0866-7187/41/4/14233

Cited by 29 publications

(23 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…According to this classification, low hazard suggests the possibility of Note: Δ = n D − n N events with magnitudes M4-4.9, while moderate hazard suggests the possibility of events with magnitudes 5-5.9. The results obtained generally do not contradict the seismic history of the study region and can be helpful for long-term seismic hazard assessment in the Corsica-Sardinia region (Rugarli et al 2019). The information about the possible locations of M5+ earthquakes fills possible gaps in known seismicity.…”

Section: Conclusion and Discussionmentioning

confidence: 54%

On the seismic potential of the Corsica–Sardinia block

Gorshkov

Panza

Soloviev

et al. 2021

Rend. Fis. Acc. Lincei

View full text Add to dashboard Cite

The Corsica-Sardinia lithospheric block is traditionally viewed as a region of notoriously low seismicity. Earthquake catalogs report only three moderate earthquakes in the range of magnitudes 5.0-5.1. The scarcity of documented seismicity in the region does not allow for the reliable assessment of the seismic hazard. In this paper, we make an attempt to evaluate the seismic potential of the Corsica-Sardinia region employing the morphostructural zoning (MSZ) that allows for the identification of locations of potential earthquakes. The MSZ delineates the hierarchical system of morphostructural blocks, the network of lineaments bounding the blocks, and the loci of nodes formed around intersections of lineaments. Nodes are treated as earthquake controlling structures. We have used the existing criteria of seismicity defined earlier for seismogenic (M5+) nodes in Iberia and the Western Alps with the goal to identify seismogenic nodes capable of generating earthquakes M5+ in the Corsica-Sardinia block. We test the criteria of seismicity for these regions relying on modern models of the Mediterranean geodynamics that view the eastern margin of Iberia and Provence adjacent to the Western Alps as locations of the Corsica-Sardinia block before drifting. Due to a common tectonic evolution the structure of the Corsica-Sardinia block is roughly similar in the basic features to the structural setting of Iberia and southern France. Out of the 81 nodes delineated by MSZ (deliberately ignoring the available earthquake catalogue) we identify 24 nodes capable of earthquakes M5+ using the criteria of seismicity defined for Iberia. Nodes hosting three documented M5+ earthquakes are assigned to seismogenic ones and most of the nodes accommodating smaller events with magnitudes 4.0-4.9 are also classified as seismogenic by pattern recognition. Applying the criteria of seismicity defined for the Western Alps, we have properly identified only two nodes hosting the documented M5+ earthquakes and missed practically all the nodes with smaller events. The performed analysis reveals that the criteria of seismicity defined for Iberia are more pertinent for the identification of seismogenic nodes in Corsica-Sardinia, because they recognize as seismogenic the nodes marked by documented earthquakes. Our study suggests that the seismic potential of the Corsica-Sardinia block can be specified as low-to-moderate. The defined locations of seismogenic nodes provide key information for knowledgeable long-term seismic hazard assessment of the region.

show abstract

Section: Conclusion and Discussionmentioning

confidence: 54%

On the seismic potential of the Corsica–Sardinia block

Gorshkov

Panza

Soloviev

et al. 2021

Rend. Fis. Acc. Lincei

View full text Add to dashboard Cite

show abstract

“…Namely, we added a safety increment ΔM= EM M to the maximum magnitude observed or estimated for the nodes (with pattern recognition of morphostructural zonation), where EM (here set to 2.0) is a tunable safety factor and M (here set to 0.25) is a value representative of the global uncertainty on magnitude determination (Båth, 1973). Rugarli et al (2019b) demonstrated that the application of this increment to the lower bound magnitude of seismogenic nodes in Italy returns hazard levels that envelope or match the 1000-years long Italian earthquake catalogue almost everywhere. They showed that the application of this ΔM increment is equivalent to applying a partial safety factor q to the seismic moment at the fault M 0 , as normally asked by Eurocodes and other international standards for typical structural design.…”

Section: Resultsmentioning

confidence: 98%

Neo-deterministic seismic hazard maps of Kosovo

et al. 2021

View full text Add to dashboard Cite

Kosovo is one of the most seismically active regions in Europe, lying within the Alpine-Mediterranean tectonic belt. Historical records for the region show several catastrophic earthquakes with epicentral intensity IX (MCS). However, due to Kosovo’s high population density, high prevalence of traditional construction, and insufficient enforcement of building codes, Kosovo is vulnerable to earthquake damage. In this study, we present earthquake hazard maps for bedrock conditions in Kosovo based on the well-known Neo-deterministic Seismic Hazard Assessment (NDSHA) method. NDSHA relies upon the fundamental physics of wave generation and propagation in complex geologic structures to generate realistic time series, used as input for the computation of several ground motion parameters, integrating the available knowledge of seismic history, seismogenic zones and morphostructural nodes. In accordance with continuum mechanics, the tensor nature of earthquake ground motion is preserved, producing realistic signals using structural models obtained by tomographic inversion and earthquake source information readily available in literature. Our maps are generally consistent with the observed intensity IX (MCS) and suggest that, in some instances, intensity X could be reached.

show abstract

“…Since by definition seismogenic nodes, which can be identified by pattern recognition via morphostructural zonation (MZ), per Gorshkov et al (2003) -accommodate earthquakes with a magnitude above a fixed threshold M (Gorshkov et al, 2002;Peresan et al, 2015;Gvishiani et al, 2020) therefore their use is recommended in the NDSHA procedure whenever either historical parametric catalogues are unavailable or, although available, they cannot be considered sufficiently complete. A comprehensive validation of seismogenic nodes as a viable alternative to both seismogenic zones and observed seismicity, for the definition of seismic hazard at regional scale, is given by Rugarli et al (2019b).…”

Section: Methodsmentioning

confidence: 99%

“…In an important recent finding, Rugarli et al (2019b) have shown, using the unique 1000 + years" catalogue available for Italy, that seismogenic nodes may represent a viable alternative to seismogenic zones and observed seismicity for the reliable definition of seismic hazard at regional scale. Their paper provides both a validation of the seismogenic nodes method, and it also further supplies a tentative tuning of the safety factor γ EM at about ≈ 2.…”

Section: "One Must Never Say Anything Too Specific About Earthquakes" -Perry Byerlymentioning

confidence: 99%

“…Therefore, we not only recommend, but also very strongly encourage its widespread application in all earthquake-prone regionsto enhance both earthquake safety of civil populations to reduce human losses, and also to provide for resilience of community economies and infrastructure. Rugarli et al, 2019b have pointed out that the consideration of a fixed increment of a given earthquake magnitude at a specific fault is very analogous to multiplying the mechanical moment at that fault by some factor, as is similarly done in structural engineering practice when determining the applied loads mandated by the most current structural engineering standards (e.g., Eurocodes). Then, in parallel with the currently accepted Eurocode 0 Paradigm (CEN EN-1990, 2002, these same authors introduced a tunable safety factor γ EM -which quantitatively captures uncertainties in the seismic moments of assessed faults.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

NDSHA - The New Paradigm for RSHA - An Updated Review

Bela

Panza

2021

TCCKHVTD

View full text Add to dashboard Cite

A New Paradigm (data driven and not like the currently model driven) is needed for Reliable Seismic Hazard Assessment RSHA. Neo-Deterministic Seismic Hazard Assessment (NDSHA) integrates earthquake geology, earthquake science, and particularly earthquake physics to finally achieve a New (and needed) Paradigm for Reliable Seismic Hazard Assessment RSHA.Although observations from many recent destructive earthquakes have all confirmed the validity of NDSHA’s approach and application to earthquake hazard forecasting-nonetheless damaging earthquakes still cannot yet be predicted with a precision requirement consistent with issuing a red alert and evacuation order to protect civil populations. However, intermediate-term (time scale) and middle-range (space scale) predictions of main shocks above a pre-assigned threshold may be properly used for the implementation of low-key preventive safety actions, as recommended by UNESCO in 1997. Furthermore, a proper integration of both seismological and geodetic information has been shown to also reliably contribute to a reduction of the geographic extent of alarms and it therefore defines a New Paradigm for TimeDependent Hazard Scenarios: Intermediate-Term (time scale) and Narrow-Range (space scale) Earthquake Prediction.

show abstract

Seismogenic nodes as a viable alternative to seismogenic zones and observed seismicity for the definition of seismic hazard at regional scale

Cited by 29 publications

References 39 publications

On the seismic potential of the Corsica–Sardinia block

On the seismic potential of the Corsica–Sardinia block

Neo-deterministic seismic hazard maps of Kosovo

NDSHA - The New Paradigm for RSHA - An Updated Review

Contact Info

Product

Resources

About