Preliminary engineering analysis of the August 24th 2016, ML 6.0 central Italy earthquake records

An earthquake of estimated local magnitude (ML) 6.0 struck central Italy on the 24th of August (01:36:32 UTC) in the vicinity of Accumoli (close to Rieti, central Italy) initiating a long-lasting seismic sequence that also featured events of larger magnitude within a few months. The earthquake caused widespread building damage and around three-hundred fatalities. Ground motion was recorded by hundreds of seis-mic stations. This work uses accelerometric records for a preliminary discussion, from the earthquake en-gineering perspective, of strong motion caused by the earthquake. Peak and integral ground motion inten-sity measures, are presented. The response spectra at some select stations are analysed with respect to the code-mandated design actions for various return periods at the recording sites. Hazard disaggregation for different return periods is discussed referring to the site of the epicentre of the earthquake. Finally, some preliminary considerations are made concerning the impact of rupture propagation on near-source ground motion; i.e., the records are scanned for traces of pulse-like forward-directivity effects.

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Rupture imaging for the 2016 August 24, Mw=6.0 central Italy earthquake, from back-projection of strong-motion array data

Annals of Geophysics ◽

10.4401/ag-7294 ◽

2016 ◽

Vol 59 ◽

Author(s):

Gilberto Saccorotti ◽

Davide Piccinini ◽

Carlo Giunchi

Keyword(s):

Waveform Inversion ◽

Central Italy ◽

Strong Motion ◽

Surface Damage ◽

Beam Power ◽

Rupture Propagation ◽

Fault Surface ◽

Seismic Displacement ◽

Motion Data ◽

Central Italy Earthquake

By extending the conventional Beam-Forming frequency-wavenumber power spectral estimate to the case of arbitrarily-shaped wavefronts, we obtained images of rupture propagation during the 2016 August 24, Mw=6.0 central Italy earthquake. Using a set of strong-motion accelerometers, we evaluate the beam power along the travel time curves associated with synthetic sources spanning a model fault surface. This allows deriving time-dependent images of the distribution of energy radiation throughout the fault plane. Results indicate bi-lateral rupture propagation toward SE and NW, in rough agreement with surface co-seismic displacement and surface damage pattern. To a first order, our results are also consistent with those obtained from full-waveform inversion of strong-motion data.

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The 1997 Umbria-Marche (central Italy) earthquake sequence: Insights on the mainshock ruptures from near source strong motion records

Geophysical Research Letters ◽

10.1029/1998gl005285 ◽

1999 ◽

Vol 26 (20) ◽

pp. 3165-3168 ◽

Cited By ~ 24

Author(s):

Aldo Zollo

Keyword(s):

Central Italy ◽

Strong Motion ◽

Earthquake Sequence ◽

Strong Motion Records ◽

Central Italy Earthquake

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Ground Response and Historical Buildings in Avellino (Campania, Southern Italy): Clues from a Retrospective View Concerning the 1980 Irpinia-Basilicata Earthquake

Geosciences ◽

10.3390/geosciences10120503 ◽

2020 ◽

Vol 10 (12) ◽

pp. 503

Author(s):

Lucia Nardone ◽

Fabrizio Terenzio Gizzi ◽

Rosalba Maresca

Keyword(s):

Seismic Hazard ◽

Ground Motion ◽

Southern Italy ◽

Strong Motion ◽

Historical Buildings ◽

Borehole Data ◽

Ground Response ◽

Maximum Acceleration ◽

Observed Damage ◽

Hazard Disaggregation

Cultural heritage represents our legacy with the past and our identity. However, to assure heritage can be passed on to future generations, it is required to put into the field knowledge as well as preventive and safeguard actions, especially for heritage located in seismic hazard-prone areas. With this in mind, the article deals with the analysis of ground response in the Avellino town (Campania, Southern Italy) and its correlation with the effects caused by the 23rd November 1980 Irpinia earthquake on the historical buildings. The aim is to get some clues about the earthquake damage cause-effect relationship. To estimate the ground motion response for Avellino, where strong-motion recordings are not available, we made use of the seismic hazard disaggregation. Then, we made extensive use of borehole data to build the lithological model so being able to assess the seismic ground response. Overall, results indicate that the complex subsoil layers influence the ground motion, particularly in the lowest period (0.1–0.5 s). The comparison with the observed damage of the selected historical buildings and the maximum acceleration expected indicates that the damage distribution cannot be explained by the surface geology effects alone.

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Concurrent Design Forces in Structures under Three-Component Orthotropic Seismic Excitation

Earthquake Spectra ◽

10.1193/1.1463040 ◽

2002 ◽

Vol 18 (1) ◽

pp. 1-17 ◽

Cited By ~ 16

Author(s):

K. Anastassiadis ◽

I. E. Avramidis ◽

P. Panetsos

Keyword(s):

Ground Motion ◽

Design Procedure ◽

Strong Motion ◽

Response Spectra ◽

Concurrent Design ◽

Motion Model ◽

Specific Point ◽

Extreme Stress ◽

Seismic Motion

According to the model of Penzien and Watabe, the three translational ground motion components on a specific point of the ground are statistically noncorrelated along a well-defined orthogonal system of axes p, w, and v, whose orientation remains reasonably stable over time during the strong motion phase of an earthquake. This orthotropic ground motion is described by three generally independent response spectra Sa, Sb, and Sc, respectively. The paper presents an antiseismic design procedure for structures according to the above seismic motion model. This design includes a) determination of the critical orientation of the seismic input, i.e., the orientation that gives the largest response, b) calculation of the maximum and the minimum values of any response quantity, and c) application of either the Extreme Stress Method or the Extreme Force Method for determining the most unfavorable combinations of several stress resultants (or sectional forces) acting concurrently at a specified section of a structural member.

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Near-Source Simulation of Strong Ground Motion in Amatrice Downtown Including Site Effects

Geosciences ◽

10.3390/geosciences11050186 ◽

2021 ◽

Vol 11 (5) ◽

pp. 186

Author(s):

Alessandro Todrani ◽

Giovanna Cultrera

Keyword(s):

Ground Motion ◽

Site Effects ◽

Central Italy ◽

Strong Motion ◽

Seismic Source ◽

Spectral Ratio ◽

Intensity Measures ◽

Standard Spectral Ratio ◽

Heavy Damage ◽

Strong Ground

On 24 August 2016, a Mw 6.0 earthquake started a damaging seismic sequence in central Italy. The historical center of Amatrice village reached the XI degree (MCS scale) but the high vulnerability alone could not explain the heavy damage. Unfortunately, at the time of the earthquake only AMT station, 200 m away from the downtown, recorded the mainshock, whereas tens of temporary stations were installed afterwards. We propose a method to simulate the ground motion affecting Amatrice, using the FFT amplitude recorded at AMT, which has been modified by the standard spectral ratio (SSR) computed at 14 seismic stations in downtown. We tested the procedure by comparing simulations and recordings of two later mainshocks (Mw 5.9 and Mw 6.5), underlining advantages and limits of the technique. The strong motion variability of simulations was related to the proximity of the seismic source, accounted for by the ground motion at AMT, and to the peculiar site effects, described by the transfer function at the sites. The largest amplification characterized the stations close to the NE hill edge and produced simulated values of intensity measures clearly above one standard deviation of the GMM expected for Italy, up to 1.6 g for PGA.

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Engineering observations on ground motion at the Van Norman Complex after the 1994 Northridge earthquake

Bulletin of the Seismological Society of America ◽

10.1785/bssa08601bs333 ◽

1996 ◽

Vol 86 (1B) ◽

pp. S333-S349 ◽

Cited By ~ 1

Author(s):

J. P. Bardet ◽

C. Davis

Keyword(s):

Ground Motion ◽

Earthquake Engineering ◽

Low Frequency ◽

Strong Motion ◽

Response Spectra ◽

Vertical Acceleration ◽

Northridge Earthquake ◽

Peak Acceleration ◽

Geotechnical Earthquake Engineering ◽

1994 Northridge Earthquake

Abstract During the 1994 Northridge earthquake, the Van Norman Complex yielded an unprecedented number of recordings with high acceleration, in the close proximity of the fault rupture. These strong-motion recordings exhibited the pulses of the main event. One station recorded the largest velocity ever instrumentally recorded (177 cm/sec), resulting from a 0.86 g peak acceleration with a low frequency. Throughout the complex, the horizontal accelerations reached peak values ranging from 0.56 to 1.0 g, except for the complex center, where the peak acceleration did not exceed 0.43 g. The vertical acceleration reached maximum peak values comparable with those of the horizontal acceleration. The acceleration response spectra in the longitudinal and transverse directions were significantly different. Such a difference, which is not yet well documented in the field of geotechnical earthquake engineering, indicates that the amplitude and frequency content of the ground motion was directionally dependent in the Van Norman Complex.

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2016–2017 Central Italy Earthquake Sequence: Seismic Retrofit Policy and Effectiveness

Earthquake Spectra ◽

10.1193/100717eqs197m ◽

2018 ◽

Vol 34 (4) ◽

pp. 1671-1691 ◽

Cited By ~ 6

Author(s):

Silvia Mazzoni ◽

Giulio Castori ◽

Carmine Galasso ◽

Paolo Calvi ◽

Richard Dreyer ◽

...

Keyword(s):

Earthquake Engineering ◽

Central Italy ◽

Companion Paper ◽

Earthquake Sequence ◽

Building Stock ◽

Ground Shaking ◽

Engineering Research ◽

Central Italy Earthquake ◽

Critical Facilities ◽

The Impact

The 2016–2017 Central Italy earthquake sequence consisted of several moderately high-magnitude earthquakes, between M5.5 and M6.5, each centered in a different location and with its own sequences of aftershocks spanning several months. To study the effects of this earthquake sequence on the built environment and the impact on the communities, a collaborative reconnaissance effort was organized by the Earthquake Engineering Research Institute (EERI), the Eucentre Foundation, the European Centre for Training and Research in Earthquake Engineering (EUCentre), and the Rete dei Laboratori Universitari di Ingegneria Sismica (ReLuis). The effort consisted of two reconnaissance missions: one following the Amatrice Earthquake of 24 August 2016 and one after the end of the earthquake sequence, in May 2017. One objective of the reconnaissance effort was to evaluate existing strengthening methodologies and assess their effectiveness in mitigating the damaging effects of ground shaking. Parallel studies by the Geotechnical Extreme Events Reconnaissance (GEER) Association, presented in a companion paper, demonstrate that variations in-ground motions due to topographic site effects had a significant impact on damage distribution in the affected area. This paper presents that, in addition to these ground motion variations, variations in the vulnerability of residential and critical facilities were observed to have a significant impact on the level of damage in the region. The damage to the historical centers of Amatrice and Norcia will be used in this evaluation: the historical center of Amatrice was devastated by the sequence of earthquakes; the significant damage in Norcia was localized to individual buildings. Amatrice has not experienced the same number of devastating earthquakes as Norcia in the last 150 years. As a result, its building stock is much older than that of Norcia and there appeared to be little visual evidence of strengthening of the buildings. The distribution of damage observed throughout the region was found to be indicative of the effectiveness of strengthening and of the need for a comprehensive implementation of retrofit policies.

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A Procedure to Select Earthquake Time Histories for Deterministic Seismic Hazard Analysis: Case Studies of Major Cities in Taiwan

10.5194/nhess-2017-33 ◽

2017 ◽

Author(s):

Duruo Huang ◽

Wenqi Du

Keyword(s):

Seismic Hazard ◽

Ground Motion ◽

Ground Surface ◽

Strong Motion ◽

Response Spectra ◽

Dynamic Responses ◽

Motion Time ◽

Acceleration Time Histories ◽

Time Histories ◽

Deterministic Seismic Hazard

Abstract. In performance-based seismic design, ground-motion time histories are needed for analyzing dynamic responses of nonlinear structural systems. However, the number of strong-motion data at design level is often limited. In order to analyze seismic performance of structures, ground-motion time histories need to be either selected from recorded strong-motion database, or numerically simulated using stochastic approaches. In this paper, a detailed procedure to select proper acceleration time histories from the Next Generation Attenuation (NGA) database for several cities in Taiwan is presented. Target response spectra are initially determined based on a local ground motion prediction equation under representative deterministic seismic hazard analyses. Then several suites of ground motions are selected for these cities using the Design Ground Motion Library (DGML), a recently proposed interactive ground-motion selection tool. The selected time histories are representatives of the regional seismic hazard, and should be beneficial to earthquake studies when comprehensive seismic hazard assessments and site investigations are yet available. Note that this method is also applicable to site-specific motion selections with the target spectra near the ground surface considering the site effect.

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Spatial Variability of Source and Attenuation Characteristics in Large Ground-Motion Datasets

10.5194/egusphere-egu2020-5187 ◽

2020 ◽

Author(s):

Sreeram Reddy Kotha ◽

Graeme Weatherill ◽

Dino Bindi ◽

Fabrice Cotton

Keyword(s):

Spatial Variability ◽

Ground Motion ◽

Ground Motions ◽

Low Frequency ◽

Strong Motion ◽

Response Spectra ◽

Large Datasets ◽

Earthquake Scenarios ◽

Crustal Earthquakes ◽

Geographical Regions

Ground-Motion Models (GMMs) characterize the random distributions of ground-motions for a combination of earthquake source, wave travel-path, and the effected site&#8217;s geological properties. Typically, GMMs are regressed over a compendium of strong ground-motion recordings collected from several earthquakes recorded at multiple sites scattered across a variety of geographical regions. The necessity of compiling such large datasets is to expand the range of magnitude, distance, and site-types; in order to regress a GMM capable of predicting realistic ground-motions for rare earthquake scenarios, e.g. large magnitudes at short distances from a reference rock site. The European Strong-Motion (ESM) dataset is one such compendium of observations from a few hundred shallow crustal earthquakes recorded at a several hundred seismic stations in Europe and Middle-East.We developed new GMMs from the ESM dataset, capable of predicting both the response spectra and Fourier spectra in a broadband of periods and frequencies, respectively. However, given the clear tectonic and geological diversity of the data, possible regional and site-specific differences in observed ground-motions needed to be quantified; whilst also considering the possible contamination of data from outliers. Quantified regional differences indicate that high-frequency ground-motions attenuate faster with distance in Italy compared to the rest of Europe, as well as systematically weaker ground-motions from central Italian earthquakes. In addition, residual analyses evidence anisotropic attenuation of low frequency ground-motions, imitating the pattern of shear-wave energy radiation. With increasing spatial variability of ground-motion data, the GMM prediction variability apparently increases. Hence, robust mixed-effects regressions and residual analyses are employed to relax the ergodic assumption.Large datasets, such as the ESM, NGA-West2, and from KiK-Net, provide ample opportunity to identify and evaluate the previously hypothesized event-to-event, region-to-region, and site-to-site differences in ground-motions. With the appropriate statistical methods, these variabilities can be quantified and applied in seismic hazard and risk predictions. We intend to present the new GMMs: their development, performance and applicability, prospective improvements and research needs.

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Strong motion accelerograph records from the 1993 Napierville earthquake

Canadian Journal of Civil Engineering ◽

10.1139/l95-017 ◽

1995 ◽

Vol 22 (1) ◽

pp. 190-196

Author(s):

René Tinawi ◽

André Filiatrault ◽

Pierre Léger

Keyword(s):

Ground Motion ◽

Energy Content ◽

Strong Motion ◽

Response Spectra ◽

High Energy ◽

Period Range ◽

Attenuation Relationships ◽

Acceleration Time Histories ◽

Short Period ◽

Time Histories

An earthquake of magnitude ML = 4.3 occurred near Napierville, Quebec, on November 16, 1993. An accelerograph at the liquefaction, storage, and regasification plant of Gaz Metropolitain in Montreal, about 55 km from the epicentre, recorded the ground motion. Although the maximum accelerations and velocities from this event are small, the acceleration time histories do confirm the high energy content in the very short period range. The recorded ground motion and corresponding absolute acceleration response spectra are presented and various attenuation relationships, proposed for eastern North America, are utilized to compare the measured and predicted ground motion parameters. Key words: Napierville earthquake, attenuation relationships, acceleration spectra, strong motion records.

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