Developing the First Intensity Prediction Equation Based on the Environmental Scale Intensity: A Case Study from Strong Normal-Faulting Earthquakes in the Italian Apennines

2020 ◽  
Vol 91 (5) ◽  
pp. 2611-2623 ◽  
Author(s):  
Maria Francesca Ferrario ◽  
Franz Livio ◽  
Stefano Serra Capizzano ◽  
Alessandro M. Michetti

Abstract Earthquakes produce effects on the built and natural environment, the severity of which decays with distance from the epicenter. Empirical relations describing the intensity attenuation with distance are fundamental for seismic hazard assessment and for deriving parameters for preinstrumental events. Seismic intensity is usually assigned based on damage to buildings and infrastructures; this can be challenging for intensity degrees higher than X or when macroseismic fields of multiple events close in time are overlapping. A complementary approach is the study of earthquake environmental effects (EEEs), which are used to assign intensity on the environmental scale intensity (ESI) scale. However, a quantitative comparison between the ESI and traditional scales, and an equation describing the ESI attenuation with distance are still lacking. Here, we analyze 14 historical and instrumental events (time window 1688–2016) in the central and southern Apennines (Italy), comparing ESI and Mercalli–Cancani–Sieberg (MCS) intensities. Our results show that ESI consistently provides higher intensity near the epicenter and the attenuation is steeper than MCS. We derive the first intensity prediction equation for the ESI scale, which computes local intensity as a function of distance and epicentral intensity value. We document that, in the near field, the MCS attenuation for shallow crustal events occurred in the twenty-first century is steeper than previous events, whereas the ESI attenuation shows a consistent behavior through time. This result questions the reliability of current empirical relations for the investigation of future events. We recommend including EEEs in intensity assignments because they can guarantee consistency through time and help in evaluating the spatial and temporal evolution of damage progression during seismic sequences, thus ultimately improving seismic risk assessment.

2020 ◽  
Vol 101 (3) ◽  
pp. 817-832
Author(s):  
Julio Mezcua ◽  
Juan Rueda ◽  
Rosa M. García Blanco

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 44
Author(s):  
Rosa Nappi ◽  
Sabina Porfido ◽  
Elisa Paganini ◽  
Luigina Vezzoli ◽  
Maria Francesca Ferrario ◽  
...  

On 21 August 2017 at 20:57 (local time) a very shallow (H = 1.2 km), moderate (Md = 4.0), earthquake hit the volcanic island of Ischia (Southern Italy), causing the death of two people. The study of the damage to the buildings with the European Macroseismic Scale 98 (EMS-98), carried out immediately after the earthquake, highlighted that hilly area of Casamicciola Terme, on the northern side of the Mt. Epomeo, was the most damaged part of the island with locally quite relevant damage (I = VIII EMS). This seismic event is the first damaging earthquake in Ischia during the instrumental era. In fact, this provides, for the first time, the opportunity to integrate historical seismicity, macroseismic observations, instrumental information, and detailed mapping of the geological coseismic effects. In this work we evaluate the effects induced by the 2017 Casamicciola earthquake on the environment using the Environmental Seismic Intensity 2007 (ESI-07) macroseismic scale. This macroseismic analysis, together with the superficial coseismic faulting characteristics and the available geophysical information, allows us to reconsider the source model for the 2017 earthquake and the previous damaging historical earthquakes in the Casamicciola Terme area. The application of the ESI scale to the Casamicciola Terme earthquake of 21 August 2017 and the assignment of seismic intensity offers better spatial resolution, as well as an increase of the time window for the assessment of the seismic hazard, allowing to reduce the implicit uncertainty in the intensity attenuation laws in this peculiar volcano-tectonic setting. Since intensity is linked to the direct measure of damage, and it is commonly used in hazard assessment, we argue that building damage at Casamicciola Terme is strongly influenced by earthquake surface faulting and near field effects, and therefore controlled by the geometry of the seismic source.


2014 ◽  
Vol 56 (6) ◽  
Author(s):  
Ioannis G. Fountoulis ◽  
Spyridon D. Mavroulis

On September 13, 1986, a shallow earthquake (Ms=6.2) struck the city of Kalamata and the surrounding areas (SW Peloponnese, Greece) resulting in 20 fatalities, over 300 injuries, extensive structural damage and many earthquake environmental effects (EEE). The main shock was followed by several aftershocks, the strongest of which occurred two days later (Ms=5.4). The EEE induced by the 1986 Kalamata earthquake sequence include ground subsidence, seismic faults, seismic fractures, rockfalls and hydrological anomalies. The maximum ESI 2007 intensity for the main shock has been evaluated as IX<sub>ESI 2007</sub>, strongly related to the active fault zones and the reactivated faults observed in the area as well as to the intense morphology of the activated Dimiova-Perivolakia graben, which is a 2nd order neotectonic structure located in the SE margin of the Kalamata-Kyparissia mega-graben and bounded by active fault zones. The major structural damage of the main shock was selective and limited to villages founded on the activated Dimiova-Perivolakia graben (IX<sub>EMS-98</sub>) and to the Kalamata city (IX<sub>EMS-98</sub>) and its eastern suburbs (IX<sub>EMS-98</sub>) located at the crossing of the prolongation of two major active fault zones of the affected area. On the contrary, damage of this size was not observed in the surrounding neotectonic structures, which were not activated during this earthquake sequence. It is concluded that both intensity scales fit in with the neotectonic regime of the area. The ESI 2007 scale complemented the EMS-98 seismic intensities and provided a completed picture of the strength and the effects of the September 13, 1986, Kalamata earthquake on the natural and the manmade environment. Moreover, it contributed to a better picture of the earthquake scenario and represents a useful and reliable tool for seismic hazard assessment.


Geosciences ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 58 ◽  
Author(s):  
Sabina Porfido ◽  
Giuliana Alessio ◽  
Germana Gaudiosi ◽  
Rosa Nappi

The application of the Environmental Seismic Intensity (ESI) scale 2007 to moderate and strong earthquakes, in different geological context all over the word, highlights the importance of Earthquake Environmental Effects (EEEs) for the assessment of seismic hazards. This Special Issue “New Perspectives in the Definition/Evaluation of Seismic Hazard through Analysis of the Environmental Effects Induced by Earthquakes” presents a collection of scientific contributions that provide a sample of the state-of-the-art in this field. Moreover the collected papers also analyze new data produced with multi-disciplinary and innovative methods essential for development of new seismic hazard models.


1995 ◽  
Vol 11 (1) ◽  
pp. 129-160 ◽  
Author(s):  
Paul C. Rizzo ◽  
N. R. Vaidya ◽  
E. Bazan ◽  
C. F. Heberling

Comparisons of response spectra from near and far-field records to those estimated by attenuation functions commonly used in evaluating seismic hazards show that these functions provide reasonable results for near-field western North American sites. However, they estimate relatively small motions for far-field eastern North American sites, which is contrary to the empirical evidence of the 1886 Charleston and 1988 Saguenay Earthquakes. Using the 1988 Saguenay records scaled for magnitude, and several western North American records scaled to account for the slower attenuation in the east, we have developed deterministic median and 84th percentile, 5 percent damped response spectra to represent ground motions from a recurrence of the 1886 Charleston Earthquake at a distance between 85 to 120 km. The resulting 84th percentile spectrum has a shape similar to, but is less severe than, the USNRC Regulatory Guide 1.60 5 percent damped spectrum tied to a peak ground acceleration of 0.2g.


2020 ◽  
Vol 110 (4) ◽  
pp. 1506-1516 ◽  
Author(s):  
Susan E. Hough ◽  
Sang-Ho Yun ◽  
Jungkyo Jung ◽  
Eric Thompson ◽  
Grace A. Parker ◽  
...  

ABSTRACT Shaking from the 6 July 2019 Mw 7.1 Ridgecrest, California, mainshock was strongly felt through southern California, but generated relatively minimal structural damage in Ridgecrest. We consider the extent to which a damage proxy map (DPM) generated from satellite-based Synthetic Aperture Radar images can detect minor damage throughout the town of Ridgecrest. The DPM does not, as expected, detect all minor structural damage to individual structures, nor can it distinguish between structural damage and earthquake-related movement that is not consequential. However, the DPM does confirm many instances of minor structural damage to larger structures and groups of smaller structures and in some instances suggests minor structural damage that is not apparent upon visual inspection. Although ambiguous identification of minor damage may not be useful to guide earthquake response, the identification of minor, possibly hidden damage is potentially useful for other purposes. Overall, the DPM confirms that structural damage was commensurate with modified Mercalli intensity no higher than 7 throughout Ridgecrest. We consider both instrumental and intensity data to explore further the distribution of near-field ground motions over the frequency range of engineering concern. Peak ground accelerations and peak ground velocities estimated from “Did You Feel It?” intensity data using the Worden et al. (2012) ground-motion intensity conversion equation (GMICE) are consistent with recorded instrumental data. Both instrumental and estimated mainshock peak accelerations are further consistent with predictions from both the Boore et al. (2014) ground-motion prediction equation (GMPE), but lower than predicted by the Atkinson and Wald (2007) and Atkinson et al. (2014) intensity prediction equations (IPEs). A GMPE such as Boore et al. (2014), which is constrained by a large global dataset, together with a well-constrained GMICE, may thus characterize expected shaking intensities for large earthquakes better than an IPE based on more limited intensity data.


2019 ◽  
Vol 176 (10) ◽  
pp. 4261-4275
Author(s):  
Roman N. Vakarchuk ◽  
Päivi Mäntyniemi ◽  
Ruben E. Tatevossian

2020 ◽  
Vol 20 (3) ◽  
pp. 743-753
Author(s):  
Yu-Sheng Sun ◽  
Hsien-Chi Li ◽  
Ling-Yun Chang ◽  
Zheng-Kai Ye ◽  
Chien-Chih Chen

Abstract. Real-time probabilistic seismic hazard assessment (PSHA) was developed in this study in consideration of its practicability for daily life and the rate of seismic activity with time. Real-time PSHA follows the traditional PSHA framework, but the statistic occurrence rate is substituted by time-dependent seismic source probability. Over the last decade, the pattern informatics (PI) method has been developed as a time-dependent probability model of seismic source. We employed this method as a function of time-dependent seismic source probability, and we selected two major earthquakes in Taiwan as examples to explore real-time PSHA. These are the Meinong earthquake (ML 6.6) of 5 February 2016 and the Hualien earthquake (ML 6.2) of 6 February 2018. The seismic intensity maps produced by the real-time PSHA method facilitated the forecast of the maximum expected seismic intensity for the following 90 d. Compared with real ground motion data from the P-alert network, our seismic intensity forecasting maps showed considerable effectiveness. This result indicated that real-time PSHA is practicable and provides useful information that could be employed in the prevention of earthquake disasters.


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