Empirical Modeling of Source Directivity Effects into a Ground-Motion Model for Central Italy

Assessing the spatial variability of seismic shaking in the epicentral area of an earthquake is one of the major challenges to be addressed in seismic hazard estimates. Among the main contributions to the ground-motion variability, source directivity plays a predominant role, inducing spectral amplifications in the direction of rupture propagations, even for small- to moderate-magnitude earthquakes. The scope of this work is to provide an empirical predictive model that can be used to modulate the ground-motion amplitudes, according to the expected source directivity effects. The proposed directivity corrective term is built for acceleration spectral ordinates, parameterizing the azimuthal trend of the leftover residuals of a fully nonergodic regional model, after removing the systematic effects of source, site, and propagation. Our study is focused on the area of Central Italy, which is dominated by a complex system of normal faults that has generated several seismic sequences in the past 30 yr. The residual analysis is carried out using the recordings of 456 events in magnitude ranging from 3.2 to 6.5, showing that about one-third of the examined earthquakes exhibit a clear ground-motion azimuthal pattern. The directivity correction model is based on three empirical relations, which describe (1) azimuthal variations modeled via a theoretical directivity factor, (2) spectral variation of directivity amplitude using a first-order Gaussian function, and (3) the correlation between moment magnitude and the period of maximum directivity effect. We demonstrated that the introduction of a source directivity correction, applied to a real-case scenario, has a considerable impact and may result in a 20% reduction of aleatory variability with respect to the uncorrected nonergodic model. This model offers an empirically based and physically consistent framework for capturing spatial variations in ground shaking, thereby improving the reliability of seismic hazard evaluations and informing risk mitigation strategies.

• Publication year

  2026

• Venue

  Bulletin of The Seismological Society of America (BSSA)

• Publication date

  2026-03-05

• Fields of study

  Not labeled

• Identifiers
  DOI 10.1785/0120250200
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar

• No claims are published for this paper.

• No concepts are published for this paper.

• ITACAext 2.0: A High-Quality Parametric Table of Strong-to-Weak Motion Recordings for Seismological and Engineering Research in Italy

  2025cited by this paper
• An Empirical Green’s Function Approach for Isolating Directivity Effects in Earthquake Ground-Motion Amplitudes

  2025cited by this paper
• Efficient incorporation of rupture directivity into probabilistic seismic hazard analysis using a deep learning–based approach

  2025cited by this paper
• A rupture directivity adjustment model and its application in seismic hazard

  2024cited by this paper
• A geostatistical modelling of empirical amplification functions and related site proxies for shaking scenarios in central Italy

  2024cited by this paper
• A Reliable Procedure to Estimate the Rupture Propagation Directions from Source Directivity: The 2016–2018 Central Italy Seismic Sequence

  2023cited by this paper
• Capturing Directivity in Probabilistic Seismic Hazard Analysis for New Zealand: Challenges, Implications, and a Machine Learning Approach for Implementation

  2023cited by this paper
• Physics-based parametrization of a FAS nonergodic ground motion model for Central Italy

  2023cited by this paper
• Including Radiation-Pattern Effects in Ground-Motion Models for Taiwan

  2023cited by this paper
• Rupture Directivity of the 25 October 2022 Mw 5.1 Alum Rock Earthquake

  2023cited by this paper
• Temporal Variation of the Spectral Decay Parameter Kappa Detected before and after the 2016 Main Earthquakes of Central Italy

  2022cited by this paper
• Empirical correlations between a FAS non-ergodic ground motion model and a GIT derived model for Central Italy

  2022cited by this paper
• NESS2.0: An Updated Version of the Worldwide Dataset for Calibrating and Adjusting Ground-Motion Models in Near Source

  2021cited by this paper
• Empirical Evidence of Frequency‐Dependent Directivity Effects From Small‐To‐Moderate Normal Fault Earthquakes in Central Italy

  2021cited by this paper
• RETRACE-3D project: A multidisciplinary collaboration to build a crustal model for the 2016-2018 central Italy seismic sequence

  2021cited by this paper
• Fault2SHA Central Apennines database and structuring active fault data for seismic hazard assessment

  2021cited by this paper
• Accounting for directivity-induced pulse-like ground motions in building portfolio loss assessment

  2020cited by this paper
• Empirical nonergodic shaking scenarios based on spatial correlation models: An application to central Italy

  2020cited by this paper
• Large Earthquakes Driven by Fluid Overpressure: The Apennines Normal Faulting System Case

  2020cited by this paper
• Fine‐Scale Structure of the 2016–2017 Central Italy Seismic Sequence From Data Recorded at the Italian National Network

  2020cited by this paper
• Empirical Models of Shear-Wave Radiation Pattern Derived from Large Datasets of Ground-Shaking Observations

  2019cited by this paper
• Summary of the BA18 Ground‐Motion Model for Fourier Amplitude Spectra for Crustal Earthquakes in California

  2019cited by this paper
• Breakdown of Earthquake Self‐Similar Scaling and Source Rupture Directivity in the 2016–2017 Central Italy Seismic Sequence

  2019cited by this paper
• Directivity Modes of Earthquake Populations with Unsupervised Learning

  2019cited by this paper
• Tectonics Inversions, Fault Segmentation, and Triggering Mechanisms in the Central Apennines Normal Fault System: Insights From High‐Resolution Velocity Models

  2018cited by this paper
• Imprint of Rupture Directivity From Ground Motions of the 24 August 2016 Mw6.2 Central Italy Earthquake

  2017cited by this paper
• Evidence for Static and Dynamic Triggering of Seismicity Following the 24 August 2016, MW = 6.0, Amatrice (Central Italy) Earthquake

  2017cited by this paper
• Rupture Directivity of the Strongest 2016–2017 Central Italy Earthquakes

  2017cited by this paper
• Uncertainty, Variability, and Earthquake Physics in Ground‐Motion Prediction Equations

  2017cited by this paper
• Investigating the effectiveness of rupture directivity during the August 24, 2016 Mw 6.0 central Italy earthquake

  2016cited by this paper
• Spectral models for ground motion prediction in the L'Aquila region (central Italy): evidence for stress-drop dependence on magnitude and depth

  2016cited by this paper
• Characteristics of the strong ground motion from the 24th August 2016 Amatrice earthquake

  2016cited by this paper
• A Local Magnitude Scale for Crustal Earthquakes in Italy

  2016cited by this paper
• Diminishing high‐frequency directivity due to a source effect: Empirical evidence from small earthquakes in the Abruzzo region, Italy

  2016cited by this paper
• Slip heterogeneity and directivity of the ML 6.0, 2016, Amatrice earthquake estimated with rapid finite‐fault inversion

  2016cited by this paper
• Rupture Directivity from Strong-Motion Recordings of the 2013 Lushan Aftershocks

  2015cited by this paper
• Along-strike rupture directivity of earthquakes of the 2009 L'Aquila, central Italy, seismic sequence

  2015cited by this paper
• Fitting Linear Mixed-Effects Models Using lme4

  2014cited by this paper
• Comparison of NGA-West2 Directivity Models

  2014cited by this paper
• High-frequency directivity effects: evidence from analysis of the Les Saintes records

  2014cited by this paper
• High‐Frequency Directivity Effect for an Mw 4.1 Earthquake, Widely Felt by the Population in Southeastern France

  2013cited by this paper
• Final Report of the NGA-West2 Directivity Working Group

  2013cited by this paper
• Combining stress transfer and source directivity: the case of the 2012 Emilia seismic sequence

  2013cited by this paper
• Rupture directivity of the 2011, Mw 5.2 Lorca earthquake (Spain)

  2012cited by this paper
• High-frequency filtering of strong-motion records

  2011cited by this paper
• An Empirically Calibrated Framework for Including the Effects of Near-Fault Directivity in Probabilistic Seismic Hazard Analysis

  2011cited by this paper
• Modelling directivity of strong ground motion with a fractal, k−2, kinematic source model

  2011cited by this paper
• The Variability of Ground-Motion Prediction Models and Its Components

  2010cited by this paper
• Resolving fault plane ambiguity for small earthquakes

  2010cited by this paper
• Rupture Directivity Characteristics of the 2003 Big Bear Sequence

  2010cited by this paper
• Near‐source seismic demand and pulse‐like records: A discussion for L'Aquila earthquake

  2010cited by this paper
• Normal faults and thrusts reactivated by deep fluids: The 6 April 2009 Mw 6.3 L'Aquila earthquake, central Italy

  2010cited by this paper
• Short baseline variations in site response and wave-propagation effects and their structural causes: Four examples in and around the santa clara valley, California

  2010cited by this paper
• Real-Time Determination of Seismic Moment Tensor for the Italian Region

  2009cited by this paper
• The 2009 L'Aquila (central Italy) MW6.3 earthquake: Main shock and aftershocks

  2009cited by this paper
• Source parameters and rupture velocity of small M ≤ 2.1 reservoir induced earthquakes

  2009cited by this paper
• EXPRESS LETTER: Seismic moment tensors of the April 2009, L'Aquila (Central Italy), earthquake sequence

  2009cited by this paper
• VECTOR-VALUED INTENSITY MEASURES FOR PULSE-LIKE NEAR-FAULT GROUND MOTIONS

  2008cited by this paper
• Directivity in NGA Earthquake Ground Motions: Analysis Using Isochrone Theory

  2008cited by this paper
• The Persistence of Directivity in Small Earthquakes

  2007cited by this paper
• Quantitative Classification of Near-Fault Ground Motions Using Wavelet Analysis

  2007cited by this paper
• Explicit Directivity-Pulse Inclusion in Probabilistic Seismic Hazard Analysis

  2007cited by this paper
• Analysis of the Frequency Dependence of the S-Wave Radiation Pattern from Local Earthquakes in Central Italy

  2006cited by this paper
• Radiation efficiency and apparent stress of small earthquakes in a South African gold mine

  2005cited by this paper
• Characterization of forward-directivity ground motions in the near-fault region

  2004cited by this paper
• Spatial and temporal variations in growth rates along active normal fault systems: an example from The Lazio–Abruzzo Apennines, central Italy

  2004cited by this paper
• Magnitude scaling of the near fault rupture directivity pulse

  2003cited by this paper
• Architecture and seismotectonics of a regional low‐angle normal fault zone in central Italy

  2000cited by this paper
• Modification of Empirical Strong Ground Motion Attenuation Relations to Include the Amplitude and Duration Effects of Rupture Directivity

  1997cited by this paper
• Empirical Green function deconvolution of broadband surface waves: rupture directivity of the 1992 Landers, California (Mw = 7.3), earthquake

  1994cited by this paper
• A kinematic self-similar rupture process for earthquakes

  1994cited by this paper
• Directivity and the Doppler effect

  1988cited by this paper
• THE INFLUENCE OF RUPTURE INCOHERENCE ON SEISMIC DIRECTIVITY

  1978cited by this paper
• Complexity of energy release during the Imperial Valley, California, earthquake of 1940

  1970cited by this paper
• Seismic displacements near a fault

  1968cited by this paper
• On the seismic body waves from a finite moving source

  1965cited by this paper
• An Algorithm for Least-Squares Estimation of Nonlinear Parameters

  1963cited by this paper
• Radiation pattern of Rayleigh waves from a fault of arbitrary dip and direction of motion in a homogeneous medium

  1962cited by this paper
• 12. An Attempt to Detect Azimuth Effect on Spectral Structures of Seismic Waves : The Alaskan Earthquake of April 7, 1958

  1960cited by this paper

• No citing papers are available for this paper.