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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.

We report a geophysical study across an active normal fault in the Southern Apennines. The surveyed area is the “Il Lago” Plain (Pettoranello del Molise), at the foot of Mt. Patalecchia (Molise Apennines, Southern Italy), a small tectonic basin filled by Holocene deposits located at the NW termination of the major Quaternary Bojano basin structure. This basin, on the NE flank of the Matese Massif, was the epicentral area of the very strong 26 July, 1805, Sant’Anna earthquake (I0 = X MCS, Mw = 6.7). The “Il Lago” Plain is bordered by a portion of the right-stepping normal fault system bounding the whole Bojano Quaternary basin (28 km long). The seismic source responsible for the 1805 earthquake is regarded as one of the most hazardous structures of the Apennines; however, the position of its NW boundary of this seismic source is debated. Geological, geomorphological and macroseismic data show that some coseismic surface faulting also occurred in correspondence with the border fault of the “Il Lago” Plain. The study of the “Il Lago” Plain subsurface might help to constrain the NW segment boundary of the 1805 seismogenic source, suggesting that it is possibly a capable fault, source for moderate (Mw < 5.5) to strong earthquakes (Mw ≥ 5.5). Therefore, we constrained the geometry of the fault beneath the plain using low-frequency Ground Penetrating Radar (GPR) data supported by seismic tomography. Seismic tomography yielded preliminary information on the subsurface structures and the dielectric permittivity of the subsoil. A set of GPR parallel profiles allowed a quick and high-resolution characterization of the lateral extension of the fault, and of its geometry at depth. The result of our study demonstrates the optimal potential of combined seismic and deep GPR surveys for investigating the geometry of buried active normal faults. Moreover, our study could be used for identifying suitable sites for paleoseismic analyses, where record of earthquake surface faulting might be preserved in Holocene lacustrine sedimentary deposits. The present case demonstrates the possibility to detect with high accuracy the complexity of a fault-zone within a basin, inferred by GPR data, not only in its shallower part, but also down to about 100 m depth.

The city of Naples (Campanian region, Southern Italy) has been hit by the strongest earthquakes located inside the seismogenic areas of the Southern Apennines, as well as by the volcano-tectonic earthquakes of the surrounding areas of the Campi Flegrei, Ischia and Vesuvius volcanic districts. An analysis of the available seismic catalogues shows that in the last millennium, more than 100 earthquakes have struck Naples with intensities rating I to III on the Mercalli&ndash, Cancani&ndash, Sieberg (MCS) scale over the felt level. Ten of these events have exceeded the damage level, with a few of these possessing an intensity greater than VII MCS. The catastrophic earthquakes of 1456 (I0 = XI MCS), 1688 (I0 = XI MCS) and 1805 (I0 = X MCS) occurred in the Campania&ndash, Molise Apennines chain, produced devastating effects on the urban heritage of the city of Naples, reaching levels of damage equal to VIII MCS. In the 20th century, the city of Naples was hit by three strong earthquakes in 1930 (I0 = X MCS), 1962 (I0 = IX MCS) and 1980 (I0 = X MCS), all with epicenters in the Campania and Basilicata regions. The last one is still deeply engraved in the collective memory, having led to the deaths of nearly 3000 individuals and resulted in the near-total destruction of some Apennine villages. Moreover, the city of Naples has also been hit by ancient historical earthquakes that originated in the Campanian volcanic districts of Campi Flegrei, Vesuvio and Ischia, with intensities up to VII&ndash, VIII MCS (highest in the Vesuvian area). Based on the intensity and frequency of its past earthquakes, the city of Naples is currently classified in the second seismic category, meaning that it is characterized by &ldquo, seismicity of medium energy&rdquo, In this paper, we determine the level of damage suffered by Naples and its monuments as a result of the strongest earthquakes that have hit the city throughout history, highlighting its repetitiveness in some areas. To this aim, we reconstructed the seismic history of some of the most representative urban monuments, using documentary and historical sources data related to the effects of strong earthquakes of the Southern Apennines on the city of Naples. The ultimate purpose of this study is to perform a seismic macro-zoning of the ancient center of city and reduce seismic risk. Our contribution represents an original elaboration on the existing literature by creating a damage-density map of the strongest earthquakes and highlighting, for the first time, the areas of the city of Naples that are most vulnerable to strong earthquakes in the future. These data could be of fundamental importance to the construction of detailed maps of seismic microzones. Our study contributes to the mitigation of seismic risk in the city of Naples, and provides useful advice that can be used to protect the historical heritage of Naples, whose historical center is a UNESCO World Heritage site.

On 21 August 2017, a shallow earthquake of Md 4.0 struck the CasamicciolaTerme village in the north of Ischia volcanic island (Italy). It caused two fatalities and heavy damage in a restricted area of a few square kilometers. Casamicciola Terme has been recurrently destroyed in the last centuries by similar volcano-tectonic earthquakes (1762, 1767, 1796, 1828, 1881, and 1883). After the catastrophic 1883 Casamicciola event (2343 casualties), this is the first heavy damaging earthquake at Ischia that provides, for the first time, the opportunity of integrating historical seismicity, macroseismic observations, instrumental information, and detailed mapping of coseismic geological effects. Soon after the 2017 mainshock we surveyed the epicentral area to collect data on the coseismic ground effects, recording more than 100 geological field observations. Mapped effects define a belt which closely follows the trace of the Casamicciola E-W-trending normal fault system, bounding the northern slope of Mt. Epomeo, previously known as a Latest Pleistocene to Holocene normal fault with a slip rate of ~3:0 cm=yr. We found significant evidence for coseismic surface faulting, testified by a main alignment of ruptures for a 2 km end-to-end length and normal dip-slip displacement of 1-3 cm. The geometry and regularity of the structural pattern, together with constant kinematics of the coseismic ruptures with the north side down, strongly suggest a primary tectonic origin for the mapped ruptures and strongly supports an E-W normal-faulting focal mechanism for the 2017 Casamicciola earthquake.Macroseismic information supports the notion that previous historical events also had a similar style of faulting.

The earthquake environmental effects (EEEs) around the epicentral area of the Pohang earthquake (Mw-5.4) that occurred on 15 November 2017 have been collected and classified using the Environmental Seismic Intensity Scale (ESI-07 scale) proposed by the International Union for Quaternary Research (INQUA) focus group. The shallow-focus 15 November Pohang earthquake did not produce any surface rupture, but caused extensive secondary environmental effects and damage to life-line structures. This earthquake was one of the most damaging earthquakes during the instrumental seismic era of the Korean Peninsula. The EEEs included extensive liquefaction, ground cracks, ground settlement, localized rockfall, and variation of the water table. The main objective of this paper was to carry forward a comparative assessment of the Pohang earthquake&rsquo, s intensity based on traditional macroseismic scales and the ESI-07 scale. With that objective, this study will also make a substantial contribution to any future revision of the ESI-07 scale, which mostly comprises case studies from Europe and South America. The comparison of the ESI-07 scale with traditional intensity scales similar to the intensity scale used by the Korean Meteorological Administration for the epicentral areas showed 1&ndash, 2-degree differences in intensity. Moreover, the ESI scale provided a clearer picture of the intensity around the epicentral area, which is mostly agricultural land with a lack of urban units or buildings. This study urges the integration of the traditional and ESI-07 scale for such small magnitude earthquakes in the Korean Peninsula as well as around the world in future. This will predict seismic intensity more precisely and hence provide a more-effective seismic hazard estimation, particularly in areas of low seismic activity. The present study will also provide a useful and reliable tool for the seismic hazard assessment of similar earthquakes around the study area and land-use planning at a local scale considering the secondary effects.

On 26th January 2001, an earthquake of magnitude Mw 7.7 occurred near Bhuj, in northwestern India, resulting in severe environmental effects. No unequivocal primary surface rupture was observed for the earthquake, but it caused widespread liquefaction and lateral spreading in the Rann of Kachchh and Little Rann. After the earthquake, several researchers collected field evidence of secondary surface rupture, rockfall, dry craters, and surface manifestations of liquefaction, including the formation of mud volcanoes and lateral spreads, in the meizoseismal area. Analysis of pre- and post-earthquake satellite images suggests that several “dry” streams in the Rann of Kachchh began to flow due to extensive liquefaction induced by the earthquake. In this present study, the macroseismic intensity of the Bhuj earthquake is evaluated by considering these environmental effects and applying the ESI-07 intensity scale to the affected area. As an outcome, the epicentral intensity of the 2001 Bhuj earthquake was determined to be XI. According to historical records and seismic catalogs, 16th June 1819 Allah Bund earthquake caused prominent surface rupture which was not so clear in the case of 2001 Bhuj earthquake, but the secondary effects were similar for both earthquakes. Considering the environmental effects caused by the 1819 Allah Bund earthquake, an intensity of XI was estimated for the epicentral area. For both earthquakes, the ESI scale yields a significant difference of one to two degrees with the traditional intensity scales. The 2001 Bhuj earthquake and 1819 Allah Bund earthquake shows similar ESI-07 intensity of XI despite of different epicentral locations. This implies the reliability of ESI-07 scale application for different earthquakes of similar dimensions in the same geological setting. This study contributes to the application of ESI-07 scale for Indian earthquakes, especially reverse faulting events, and to the future improvement of the ESI scale with emphasis on its applicability to historical earthquakes on the Indian subcontinent. Also, this study may help in future land use planning in the meizoseismal area of 1919 Allah Bund and 2001 Bhuj earthquakes.

A hazard assessment of the 1976 Guatemala earthquake (M = 7.5) was conducted to achieve a better definition of the seismic hazard. The assessment was based on the environmental effects that had effectively contributed to the high destructive impact of that event. An interdisciplinary approach was adopted by integrating: (1) historical data, (2) co-seismic geological effects in terms of Environmental Seismic Intensity (ESI) scale intensity values, and (3) ground shaking data estimated by a probabilistic/deterministic approach. A detailed analysis of primary and secondary effects was conducted for a set of 24 localities, to obtain a better evaluation of seismic intensity. The new intensity values were compared with the Modified Mercalli Intensity (MMI) and Peak Ground Acceleration (PGA) distribution estimated using a probabilistic/deterministic hazard analysis approach for the target area. Our results are evidence that the probabilistic/deterministic hazard analysis procedures may result in very different indications on the PGA distributions. Moreover, PGA values often display significant discrepancy from the macroseismic intensity values calculated with the ESI scale. Therefore, the incorporation of the environmental earth effects into the probabilistic/deterministic hazard analysis appears to be mandatory in order to achieve a more accurate seismic estimation.

The main objective of this paper was to introduce the Environmental Seismic Intensity scale (ESI), a new scale developed and tested by an interdisciplinary group of scientists (geologists, geophysicists and seismologists) in the frame of the International Union for Quaternary Research (INQUA) activities, to the widest community of earth scientists and engineers dealing with seismic hazard assessment. This scale defines earthquake intensity by taking into consideration the occurrence, size and areal distribution of earthquake environmental effects (EEE), including surface faulting, tectonic uplift and subsidence, landslides, rock falls, liquefaction, ground collapse and tsunami waves. Indeed, EEEs can significantly improve the evaluation of seismic intensity, which still remains a critical parameter for a realistic seismic hazard assessment, allowing to compare historical and modern earthquakes. Moreover, as shown by recent moderate to large earthquakes, geological effects often cause severe damage''; therefore, their consideration in the earthquake risk scenario is crucial for all stakeholders, especially urban planners, geotechnical and structural engineers, hazard analysts, civil protection agencies and insurance companies. The paper describes background and construction principles of the scale and presents some case studies in different continents and tectonic settings to illustrate its relevant benefits. ESI is normally used together with traditional intensity scales, which, unfortunately, tend to saturate in the highest degrees. In this case and in unpopulated areas, ESI offers a unique way for assessing a reliable earthquake intensity. Finally, yet importantly, the ESI scale also provides a very convenient guideline for the survey of EEEs in earthquake-stricken areas, ensuring they are catalogued in a complete and homogeneous manner

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.

The study of hydrological variations in the watersheds of seismic areas can be useful in order to acquire a new knowledge of the mechanisms by which earthquakes can produce hydrological anomalies. Italy has the availability of many long historical series both of hydrological parameters and of seismological data, and is an ideal laboratory to verify the validity of theoretical models proposed by various authors. In this work we analyse the hydrological anomalies associated with some of the big earthquakes that occurred in the last century in the southern Apennines: 1930, 1980 and 1984. For these earthquakes we analysed hydrometric and pluviometric data looking for significant anomalies in springs, water wells and mountain streams. The influence of rainfalls on the normal flows of rivers, springs and wells has been ascertained. Also, the earthquake of 1805, for which a lot of hydrological perturbations have been reported, is considered in order to point out effects imputable to this earthquake that can be similar to the effects of the other big earthquakes. The considered seismic events exhibit different modes of energy release, different focal mechanisms and different propagation of effects on the invested areas. Furthermore, even if their epicentres were not localised in contiguous seismogenetic areas, it seems that the hydrological effects imputable to them took place in the same areas. Such phenomena have been compared with macroseismic fields and transformed in parameters, in order to derive empirical relationships between the dimensions of the event and the characteristics of the hydrological variations. The results of this work point to a close dependence among hydrological anomalies, regional structures and fault mechanisms, and indicate that many clear anomalies have been forerunners of earthquakes. In 1993, the Naples Bureau of the Hydrographic National Service started the continuous monitoring of hydrologic parameters by a network of automatic stations and transmission in real time; presently 7 acquifers are under control in which also pH, T , salinity, electrical conductivity, dissolved oxygen are measured. We envisage to increase the number of monitoring sites and controlled parameters.

The aim of this study was to provide a contribution to seismic hazard assessment of the Salento Peninsula (Apulia, southern Italy). It is well known that this area was struck by the February 20, 1743, earthquake (I 0 = IX and M w = 7.1), the strongest seismic event of Salento, that caused the most severe damage in the towns of Nardo (Lecce) and Francavilla Fontana (Brindisi), in the Ionian Islands (Greece) and in the western coast of Albania. It was also widely felt in the western coast of Greece, in Malta Islands, in southern Italy and in some localities of central and northern Italy. Moreover, the area of the Salento Peninsula has also been hit by several low-energy and a few high-energy earthquakes over the last centuries; the instrumental recent seismicity is mainly concentrated in the western sector of the peninsula and in the Otranto Channel. The Salento area has also experienced destructive seismicity of neighboring regions in Italy (the Gargano Promontory in northern Apulia, the Southern Apennines chain, the Calabrian Arc) and in the Balkan Peninsula (Greece and Albania). Accordingly, a critical analysis of several documentary and historical sources, as well as of the geologic–geomorphologic ground effects due to the strong 1743 Salento earthquake, has been carried out by the authors in this paper; the final purpose has been to re-evaluate the 1743 MCS macroseismic intensities and to provide a list of newly classified localities according to the ESI-07 scale on the base of recognized Earthquake Environmental Effects. The result is a quite different damage scenario due to this earthquake that could raise the seismic potential currently recognized for the Salento area, and consequently upgrade the seismic hazard classification of the Salento. Indeed it is important to remind that currently, despite the intense earthquake activity recorded not only in the Otranto Channel, but especially in Greece and Albania, this area is classified in the least dangerous category of the Seismic Classification of the Italian territory (IV category).