@article{NievasPilzPrehnetal.2022,
  author    = {Nievas, Cecilia and Pilz, Marco and Prehn, Karsten and Schorlemmer, Danijel and Weatherill, Graeme and Cotton, Fabrice},
  title     = {Calculating earthquake damage building by building},
  series = {Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering},
  volume    = {20},
  journal   = {Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering},
  number    = {3},
  publisher = {Springer},
  address   = {Dordrecht},
  issn      = {1570-761X},
  doi       = {10.1007/s10518-021-01303-w},
  pages     = {1519 -- 1565},
  year      = {2022},
  abstract  = {The creation of building exposure models for seismic risk assessment is frequently challenging due to the lack of availability of detailed information on building structures. Different strategies have been developed in recent years to overcome this, including the use of census data, remote sensing imagery and volunteered graphic information (VGI). This paper presents the development of a building-by-building exposure model based exclusively on openly available datasets, including both VGI and census statistics, which are defined at different levels of spatial resolution and for different moments in time. The initial model stemming purely from building-level data is enriched with statistics aggregated at the neighbourhood and city level by means of a Monte Carlo simulation that enables the generation of full realisations of damage estimates when using the exposure model in the context of an earthquake scenario calculation. Though applicable to any other region of interest where analogous datasets are available, the workflow and approach followed are explained by focusing on the case of the German city of Cologne, for which a scenario earthquake is defined and the potential damage is calculated. The resulting exposure model and damage estimates are presented, and it is shown that the latter are broadly consistent with damage data from the 1978 Albstadt earthquake, notwithstanding the differences in the scenario. Through this real-world application we demonstrate the potential of VGI and open data to be used for exposure modelling for natural risk assessment, when combined with suitable knowledge on building fragility and accounting for the inherent uncertainties.},
  language  = {en}
}
@phdthesis{Pilz2010,
  author    = {Pilz, Marco},
  title     = {A comparison of proxies for seismic site conditions and amplification for the large urban area of Santiago de Chile},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-52961},
  school      = {Universit{\"a}t Potsdam},
  year      = {2010},
  abstract  = {Situated in an active tectonic region, Santiago de Chile, the country´s capital with more than six million inhabitants, faces tremendous earthquake hazard. Macroseismic data for the 1985 Valparaiso and the 2010 Maule events show large variations in the distribution of damage to buildings within short distances indicating strong influence of local sediments and the shape of the sediment-bedrock interface on ground motion. Therefore, a temporary seismic network was installed in the urban area for recording earthquake activity, and a study was carried out aiming to estimate site amplification derived from earthquake data and ambient noise. The analysis of earthquake data shows significant dependence on the local geological structure with regards to amplitude and duration. Moreover, the analysis of noise spectral ratios shows that they can provide a lower bound in amplitude for site amplification and, since no variability in terms of time and amplitude is observed, that it is possible to map the fundamental resonance frequency of the soil for a 26 km x 12 km area in the northern part of the Santiago de Chile basin. By inverting the noise spectral rations, local shear wave velocity profiles could be derived under the constraint of the thickness of the sedimentary cover which had previously been determined by gravimetric measurements. The resulting 3D model was derived by interpolation between the single shear wave velocity profiles and shows locally good agreement with the few existing velocity profile data, but allows the entire area, as well as deeper parts of the basin, to be represented in greater detail. The wealth of available data allowed further to check if any correlation between the shear wave velocity in the uppermost 30 m (vs30) and the slope of topography, a new technique recently proposed by Wald and Allen (2007), exists on a local scale. While one lithology might provide a greater scatter in the velocity values for the investigated area, almost no correlation between topographic gradient and calculated vs30 exists, whereas a better link is found between vs30 and the local geology. When comparing the vs30 distribution with the MSK intensities for the 1985 Valparaiso event it becomes clear that high intensities are found where the expected vs30 values are low and over a thick sedimentary cover. Although this evidence cannot be generalized for all possible earthquakes, it indicates the influence of site effects modifying the ground motion when earthquakes occur well outside of the Santiago basin. Using the attained knowledge on the basin characteristics, simulations of strong ground motion within the Santiago Metropolitan area were carried out by means of the spectral element technique. The simulation of a regional event, which has also been recorded by a dense network installed in the city of Santiago for recording aftershock activity following the 27 February 2010 Maule earthquake, shows that the model is capable to realistically calculate ground motion in terms of amplitude, duration, and frequency and, moreover, that the surface topography and the shape of the sediment bedrock interface strongly modify ground motion in the Santiago basin. An examination on the dependency of ground motion on the hypocenter location for a hypothetical event occurring along the active San Ram{\´o}n fault, which is crossing the eastern outskirts of the city, shows that the unfavorable interaction between fault rupture, radiation mechanism, and complex geological conditions in the near-field may give rise to large values of peak ground velocity and therefore considerably increase the level of seismic risk for Santiago de Chile.},
  language  = {en}
}
@article{PilzCotton2019,
  author    = {Pilz, Marco and Cotton, Fabrice},
  title     = {Does the One-Dimensional Assumption Hold for Site Response Analysis?},
  series = {Earthquake spectra : the professional journal of the Earthquake Engineering Research Institute},
  volume    = {35},
  journal   = {Earthquake spectra : the professional journal of the Earthquake Engineering Research Institute},
  number    = {2},
  publisher = {Earthquake Engineering Research Institute},
  address   = {Oakland},
  issn      = {8755-2930},
  doi       = {10.1193/050718EQS113M},
  pages     = {883 -- 905},
  year      = {2019},
  abstract  = {The one-dimensional (1-D) approach is still the dominant method to incorporate site effects in engineering applications. To bridge the 1-D to multidimensional site response analysis, we develop quantitative criteria and a reproducible method to identify KiK-net sites with significant deviations from 1-D behavior. We found that 158 out of 354 show two-dimensional (2-D) and three-dimensional (3-D) effects, extending the resonance toward shorter periods at which 2-D or 3-D site effects exceed those of the classic 1-D configurations and imposing an additional amplification to that caused by the impedance contrast alone. Such 2-D and 3-D effects go along with a large within-station ground motion variability. Remarkably, these effects are found to be more pronounced for small impedance contrasts. While it is hardly possible to identify common features in ground motion behavior for stations with similar topography typologies, it is not over-conservative to apply a safety factor to account for 2-D and 3-D site effects in ground motion modeling.},
  language  = {en}
}
@misc{PilzCottonRazafindrakotoetal.2020,
  author    = {Pilz, Marco and Cotton, Fabrice and Razafindrakoto, Hoby Njara Tendrisoa and Weatherill, Graeme and Spies, Thomas},
  title     = {Regional broad-band ground-shaking modelling over extended and thick sedimentary basins},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {2},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-57165},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-571655},
  pages     = {25},
  year      = {2020},
  abstract  = {The simulation of broad-band (0.1 to 10 + Hz) ground-shaking over deep and spatially extended sedimentary basins at regional scales is challenging. We evaluate the ground-shaking of a potential M 6.5 earthquake in the southern Lower Rhine Embayment, one of the most important areas of earthquake recurrence north of the Alps, close to the city of Cologne in Germany. In a first step, information from geological investigations, seismic experiments and boreholes is combined for deriving a harmonized 3D velocity and attenuation model of the sedimentary layers. Three alternative approaches are then applied and compared to evaluate the impact of the sedimentary cover on ground-motion amplification. The first approach builds on existing response spectra ground-motion models whose amplification factors empirically take into account the influence of the sedimentary layers through a standard parameterization. In the second approach, site-specific 1D amplification functions are computed from the 3D basin model. Using a random vibration theory approach, we adjust the empirical response spectra predicted for soft rock conditions by local site amplification factors: amplifications and associated ground-motions are predicted both in the Fourier and in the response spectra domain. In the third approach, hybrid physics-based ground-motion simulations are used to predict time histories for soft rock conditions which are subsequently modified using the 1D site-specific amplification functions computed in method 2. For large distances and at short periods, the differences between the three approaches become less notable due to the significant attenuation of the sedimentary layers. At intermediate and long periods, generic empirical ground-motion models provide lower levels of amplification from sedimentary soils compared to methods taking into account site-specific 1D amplification functions. In the near-source region, hybrid physics-based ground-motions models illustrate the potentially large variability of ground-motion due to finite source effects.},
  language  = {en}
}
@article{PilzCottonRazafindrakotoetal.2020,
  author    = {Pilz, Marco and Cotton, Fabrice and Razafindrakoto, Hoby Njara Tendrisoa and Weatherill, Graeme and Spies, Thomas},
  title     = {Regional broad-band ground-shaking modelling over extended and thick sedimentary basins},
  series = {Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering},
  volume    = {19},
  journal   = {Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering},
  number    = {2},
  publisher = {Springer},
  address   = {Dordrecht},
  issn      = {1570-761X},
  doi       = {10.1007/s10518-020-01004-w},
  pages     = {581 -- 603},
  year      = {2020},
  abstract  = {The simulation of broad-band (0.1 to 10 + Hz) ground-shaking over deep and spatially extended sedimentary basins at regional scales is challenging. We evaluate the ground-shaking of a potential M 6.5 earthquake in the southern Lower Rhine Embayment, one of the most important areas of earthquake recurrence north of the Alps, close to the city of Cologne in Germany. In a first step, information from geological investigations, seismic experiments and boreholes is combined for deriving a harmonized 3D velocity and attenuation model of the sedimentary layers. Three alternative approaches are then applied and compared to evaluate the impact of the sedimentary cover on ground-motion amplification. The first approach builds on existing response spectra ground-motion models whose amplification factors empirically take into account the influence of the sedimentary layers through a standard parameterization. In the second approach, site-specific 1D amplification functions are computed from the 3D basin model. Using a random vibration theory approach, we adjust the empirical response spectra predicted for soft rock conditions by local site amplification factors: amplifications and associated ground-motions are predicted both in the Fourier and in the response spectra domain. In the third approach, hybrid physics-based ground-motion simulations are used to predict time histories for soft rock conditions which are subsequently modified using the 1D site-specific amplification functions computed in method 2. For large distances and at short periods, the differences between the three approaches become less notable due to the significant attenuation of the sedimentary layers. At intermediate and long periods, generic empirical ground-motion models provide lower levels of amplification from sedimentary soils compared to methods taking into account site-specific 1D amplification functions. In the near-source region, hybrid physics-based ground-motions models illustrate the potentially large variability of ground-motion due to finite source effects.},
  language  = {en}
}
@article{PilzCottonZaccarellietal.2019,
  author    = {Pilz, Marco and Cotton, Fabrice and Zaccarelli, Riccardo and Bindi, Dino},
  title     = {Capturing Regional Variations of Hard-Rock Attenuation in Europe},
  series = {Bulletin of the Seismological Society of America},
  volume    = {109},
  journal   = {Bulletin of the Seismological Society of America},
  number    = {4},
  publisher = {Seismological Society of America},
  address   = {Albany},
  issn      = {0037-1106},
  doi       = {10.1785/0120190023},
  pages     = {1401 -- 1418},
  year      = {2019},
  abstract  = {A proper assessment of seismic reference site conditions has important applications as they represent the basis on which ground motions and amplifications are generally computed. Besides accounting for the average S-wave velocity over the uppermost 30 m (V-S30), the parameterization of high-frequency ground motions beyond source-corner frequency received significant attention. kappa, an empirical parameter introduced by Anderson and Hough (1984), is often used to represent the spectral decay of the acceleration spectrum at high frequencies. The lack of hard-rock records and the poor understanding of the physics of kappa introduced significant epistemic uncertainty in the final seismic hazard of recent projects. Thus, determining precise and accurate regional hard-rock kappa(0) values is critical. We propose an alternative procedure for capturing the reference kappa(0) on regional scales by linking thewell-known high-frequency attenuation parameter kappa and the properties of multiple-scattered coda waves. Using geological and geophysical data around more than 1300 stations for separating reference and soft soil sites and based on more than 10,000 crustal earthquake recordings, we observe that kappa(0) from multiple-scattered coda waves seems to be independent of the soil type but correlated with the hard-rock kappa(0), showing significant regional variations across Europe. The values range between 0.004 s for northern Europe and 0.020 s for the southern and southeastern parts. On the other hand, measuring kappa (and correspondingly kappa(0)) on the S-wave window (as classically proposed), the results are strongly affected by transmitted (reflected, refracted, and scattered) waves included in the analyzed window biasing the proper assessment of kappa(0). This effect is more pronounced for soft soil sites. In this way, kappa(coda)(0) can serve as a proxy for the regional hard-rock kappa(0) at the reference sites.},
  language  = {en}
}
@article{PilzCottonZhu2021,
  author    = {Pilz, Marco and Cotton, Fabrice and Zhu, Chuanbin},
  title     = {How much are sites affected by 2-D and 3-D site effects?},
  series = {Geophysical journal international},
  volume    = {228},
  journal   = {Geophysical journal international},
  number    = {3},
  publisher = {Oxford University Press},
  address   = {Oxford},
  issn      = {0956-540X},
  doi       = {10.1093/gji/ggab454},
  pages     = {1992 -- 2004},
  year      = {2021},
  abstract  = {1-D site response analysis dominates earthquake engineering practice, while local 2-D/3-D models are often required at sites where the site response is complex. For such sites, the 1-D representation of the soil column can account neither for topographic effects or dipping layers nor for locally generated horizontally propagating surface waves. It then remains a crucial task to identify whether the site response can be modelled sufficiently precisely by 1-D analysis. In this study we develop a method to classify sites according to their 1-D or 2-D/3-D nature. This classification scheme is based on the analysis of surface earthquake recordings and the evaluation of the variability and similarity of the horizontal Fourier spectra. The taxonomy is focused on capturing significant directional dependencies and interevent variabilities indicating a more probable 2-D/3-D structure around the site causing the ground motion to be more variable. While no significant correlation of the 1-D/3-D site index with environmental parameters and site proxies seems to exist, a reduction in the within-site (single-station) variability is found. The reduction is largest (up to 20 per cent) for purely 1-D sites. Although the taxonomy system is developed using surface stations of the KiK-net network in Japan as considerable additional information is available, it can also be applied to any (non-downhole array) site.},
  language  = {en}
}
@article{PilzIskenFlemingetal.2021,
  author    = {Pilz, Marco and Isken, Marius Paul and Fleming, Kevin and Orunbaev, Sagynbek and Moldobekov, Bolot},
  title     = {Long- and short-term monitoring of a dam in response to seasonal changes and ground motion loading},
  series = {Pure and applied geophysics : PAGEOPH ; continuation of Geofisica pura e applicata},
  volume    = {178},
  journal   = {Pure and applied geophysics : PAGEOPH ; continuation of Geofisica pura e applicata},
  number    = {10},
  publisher = {Birkh{\"a}user},
  address   = {Basel},
  issn      = {0033-4553},
  doi       = {10.1007/s00024-021-02861-5},
  pages     = {4001 -- 4020},
  year      = {2021},
  abstract  = {An experimental multi-parameter structural monitoring system has been installed on the Kurpsai dam, western Kyrgyz Republic. This system consists of equipment for seismic and strain measurements for making longer- (days, weeks, months) and shorter- (minutes, hours) term observations, dealing with, for example seasonal (longer) effects or the response of the dam to ground motion from noise or seismic events. Fibre-optic strain sensors allow the seasonal and daily opening and closing of the spaces between the dam's segments to be tracked. For the seismic data, both amplitude (in terms of using differences in amplitudes in the Fourier spectra for mapping the modes of vibration of the dam) and their time-frequency distribution for a set of small to moderate seismic events are investigated and the corresponding phase variabilities (in terms of lagged coherency) are evaluated. Even for moderate levels of seismic-induced ground motion, some influence on the structural response can be detected, which then sees the dam quickly return to its original state. A seasonal component was identified in the strain measurements, while levels of noise arising from the operation of the dam's generators and associated water flow have been provisionally identified.},
  language  = {en}
}
@article{PilzParolaiLeytonetal.2009,
  author    = {Pilz, Marco and Parolai, Stefano and Leyton, Felipe and Campos, Jaime and Zschau, Jochen},
  title     = {A comparison of site response techniques using earthquake data and ambient seismic noise analysis in the large urban areas of Santiago de Chile},
  issn      = {0956-540X},
  doi       = {10.1111/j.1365-246X.2009.04195.x},
  year      = {2009},
  abstract  = {Situated in an active tectonic region, Santiago de Chile, the country's capital with more than six million inhabitants, faces tremendous earthquake risk. Macroseismic data for the 1985 Valparaiso event show large variations in the distribution of damage to buildings within short distances, indicating strong effects of local sediments on ground motion. Therefore, a temporary seismic network was installed in the urban area for recording earthquake activity and a study was carried out aiming to estimate site amplification derived from horizontal-to- vertical (H/V) spectral ratios from earthquake data (EHV) and ambient noise (NHV), as well as using the standard spectral ratio (SSR) technique with a nearby reference station located on igneous rock. The results lead to the following conclusions: The analysis of earthquake data shows significant dependence on the local geological structure with respect to amplitude and duration. An amplification of ground motion at frequencies higher than the fundamental one can be found. This amplification would not be found when looking at NHV ratios alone. The analysis of NHV spectral ratios shows that they can only provide a lower bound in amplitude for site amplification. P-wave site responses always show lower amplitudes than those derived by S waves, and sometimes even fail to provide some frequencies of amplification. No variability in terms of time and amplitude is observed in the analysis of the H/V ratio of noise. Due to the geological conditions in some parts of the investigated area, the fundamental resonance frequency of a site is difficult to estimate following standard criteria proposed by the SESAME consortium, suggesting that these are too restrictive under certain circumstances.},
  language  = {en}
}
@article{PilzParolaiPicozzietal.2011,
  author    = {Pilz, Marco and Parolai, Stefano and Picozzi, Matteo and Zschau, Jochen},
  title     = {Evaluation of proxies for seismic site conditions in large urban areas the example of Santiago de Chile},
  series = {Physics and chemistry of the earth},
  volume    = {36},
  journal   = {Physics and chemistry of the earth},
  number    = {16},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {1474-7065},
  doi       = {10.1016/j.pce.2011.01.007},
  pages     = {1259 -- 1266},
  year      = {2011},
  abstract  = {Characterizing the local site response in large cities is an important step towards seismic hazard assessment. To this regard, single station seismic noise measurements were carried out at 146 sites in the northern part of Santiago de Chile. This extensive survey allowed the fundamental resonance frequency of the sedimentary cover, derived from horizontal-to-vertical (H/V) spectral ratios, to be mapped. By inverting the spectral ratios under the constraint of the thickness of the sedimentary cover, known from previous gravimetric measurements, local S-wave velocity profiles have been retrieved. After interpolation between the individual profiles, the resulting high resolution 3D S-wave velocity model allows the entire area, as well as deeper parts of the basin, to be represented in great detail. Since one lithology shows a great scatter in the velocity values only a very general correlation between S-wave velocity in the uppermost 30 m (v(s)(30)) and local geology is found. Local S-wave velocity profiles can serve as a key factor in seismic hazard assessment, since they allow an estimate of the amplification potential of the sedimentary cover. Mapping the intensity distribution of the 27 February 2010 Maule, Chile, event (Mw = 8.8) the results indicate that local amplification of the ground motion might partially explain the damage distribution and encourage the use of the low cost seismic noise techniques for the study of seismic site effects.},
  language  = {en}
}