Análisis de la evaluación de daños en edificios basada en imágenes de satélite y aéreas en el ámbito de Copernicus EMS Mapping

El Servicio de Gestión de Emergencias de Copernicus (Copernicus EMS del inglés, Copernicus Emergency Management Service) es un programa financiado con fondos públicos de la Unión Europea y coordinado por la Comisión Europea que proporciona a todos los actores involucrados en la gestión de desastres naturales, situaciones de emergencia y crisis humanitarias información geoespacial, principalmente basada en imágenes de satélite. Incluye componentes de Alerta temprana y Monitoreo, y de Mapeo con un módulo de Validación encargado de la evaluación de la calidad de los productos y el fomento de su mejora, en el marco del cual se realizó este estudio. Dentro del portafolio de productos de mapeo, los productos de clasificación de daños tienen como objetivo evaluar la intensidad y distribución espacial del daño resultante de un evento en edificios, bloques de viviendas o usos del suelo. Las categorías de daños para edificios y bloques de viviendas se definieron inicialmente con base en la Escala Macrosísmica Europea-1998 (EMS-98, del inglés European Macroseismic Scale). Este artículo muestra la función doble del módulo de validación. Por un lado, el artículo muestra los resultados de la validación de cuatro mapas de daños en edificios realizados por Copernicus EMS y por otro analiza la aptitud de la Escala Macrosísmica Europea (EMS-98), concebida para asignar daño in situ, para categorizar daño en edificios a partir de distintos tipos de imágenes (imágenes de satélite, imágenes oblicuas y ortofotos). La principal conclusión es que las categorías EMS-98 no se pueden traducir directamente para la evaluación de daños con base en imágenes de satélite y, en su lugar, se podría utilizar un enfoque operativo, en línea con estudios anteriores.

Inhomogeneity of Macroseismic Intensities in Italy and Consequences for Macroseismic Magnitude Estimation

We show that macroseismic intensities assessed in Italy in the last decade are not homogeneous with those of the previous periods. This is partly related to the recent adoption of the European Macroseismic Scale (EMS) in place of the Mercalli–Cancani–Sieberg (MCS) scale used up to about one decade ago. The underestimation of EMS with respect to MCS is about a half of a degree on average and, even more significant, if the MCS intensities are estimated according to the approach developed for the quick evaluations of damage by macroseismic seismologists of the Italian Department of Civil Protection. We also show the inhomogeneity over time of the average differences between instrumental and macroseismic magnitudes computed from intensity data, indicating an average overestimation of magnitudes of about 0.3 units for the instrumental ones before year 1960 and of about 0.2 units for the macroseismic ones after such date. This is consistent with previous studies that hypothesized the incorrect calibration of mechanical recording seismometers operating in Italy and in the surrounding countries before the introduction of the standard electromagnetic seismometers from the beginning of 1960s. For such reasons, the magnitudes of preinstrumental earthquakes in the Catalogo Parametrico dei Terremoti Italiani seismic catalog, used for the most recent seismic hazard assessment in Italy, might be overestimated, on average, by about 0.1–0.2 magnitude units.

Is an Earthquake Felt Inside a Car?

The analysis of how an earthquake is felt was addressed with the data provided by citizens through a website dedicated to the perception of earthquakes in Italy (Data and Resources). The analysis focused on the perception of earthquakes by observers inside both parked and moving cars. These situations were compared with outdoor ones. The felt percentage of each situation was quantified for epicentral distance ranges and European Macroseismic Scale (EMS) degree. One of the main findings was the greatest sensitivity to shaking for people inside parked cars due to resonance phenomena of the automobile–observer system. The distribution of the intensity of perception in the car was analyzed as a function of the hypocentral distance and the magnitude of the earthquake. It was possible to define the attenuation trends of these intensities. The comparison of these trends with those of the equations for estimation of response spectral ordinates allowed us to have an evaluation of the frequency values of the seismic waves that caused the vibrations felt, which were found to agree with the typical frequencies of the car–observer system, as highlighted by independent studies. The results of this analysis show the possibility to include the perception of the earthquake inside a parked and moving car among the diagnostics used in the definition of macroseismic intensity degree of the EMS.

The 2017, MD = 4.0, Casamicciola Earthquake: ESI-07 Scale Evaluation and Implications for the Source Model

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.

Models of the macroseismic field earthquakes and their influence on seismic hazard assessment values for Central Asia

Seismic intensity assessment in points of a macroseismic scale plays an important role for researching the seismic history of areas characterized by active seismicity, as well as for construction (and updating) of seismic zoning maps in various scales. Macroseismic scale points are generally referred to in construction standards applied in the majority of post-Soviet states. In our study aimed to model the macroseismic field of earthquakes, a large volume of macroseismic data on Central Asia was analyzed, and coefficients used in Blake–Shebalin and Covesligeti equations were aligned. This article presents a generalized dependence model of macroseismic intensity attenuation with distance. The model takes into account seismic load features determined by various depths of earthquakes. The ratios of small and big axes of the ellipse, that approximates real isoseists, are estimated with respect to seismic scale points, earthquake depths and magnitudes. The East Uzbekistan area is studied as an example to investigate whether seismic hazard assessment values may differ depending on a chosen law of seismic influence intensity attenuation with distance.

EMS and MCS macroseismic intensities assessed in Italy are equivalent?

<p>The most of intensity assessments provided by the large (more than 100000 intensity observations) Italian macroseismic database (DBMI15) were made using the traditional Mercalli-Cancani-Sieberg (MCS) scale but in most recent macroseismic surveys in Italy even the European Macroseismic Scale (EMS) scale was used by some research groups. In principle, MCS and EMS scales should give almost the same intensities if only damage to traditional masonry buildings is considered for MCS estimates. Some doubts remain on this equivalence even if MCS and EMS intensities were actually used as they were coincident, as in the case of or the compilation of the CPTI15 catalog used for seismic hazard assessment in Italy. In this work we compared intensity estimates made using both scales for the traditional (expert) estimates made for the same localities of some recent earthquakes as well as community intensities provided by on line questionnaires “Hai Sentito Il Terremoto” (HSIT) collected by INGV. We computed linear regressions between the two sets of intensity estimates and also compared the earthquake parameters (locations magnitude and fault orientations) computed by the Boxer code, using independently the two sets of intensities.</p>

Analysis of the 2016 Amatrice earthquake macroseismic data

On August 24, 2016, a sudden MW 6.0 seismic event hit Central Italy, causing 298 victims and significant damage to residential buildings and cultural heritage. In the days following the mainshock, a macroseismic survey was conducted by teams of the University of Padova, according to the European Macroseismic Scale (EMS98). In this contribution, a critical analysis of the collected macroseismic data is presented and some comparisons were performed with the recent 2012 Emilia sequence.