Environmental Seismic Intensity Research Articles

Reappraisal of the 2012 magnitude (MW) 6.7 Negros Oriental (Philippines) earthquake intensity and ShakeMap generation by using ESI-2007 environmental effects

The macroseismic intensity of the February 6, 2012, Negros Oriental earthquake (MW 6.7), which affected the islands of Negros and Cebu, central Philippines, has been reassessed in this study using the Environmental Seismic Intensity Scale (ESI-2007). This earthquake caused a ∼75-km-long surface rupture along a previously unmapped fault and resulted in extensive landslides, localized liquefaction, lateral spreading, a tsunami, and widespread damage to infrastructure near the epicentral area. Considering the widespread earthquake environmental effects (EEEs), ESI-2007 intensities were evaluated for 324 locations covering an area of approximately 1000 km2 within the Negros and Cebu Islands. A systematic comparison was conducted between the ESI-2007 scale and the traditional intensity scales (PHIVOLCS earthquake intensity scale (PEIS) and Modified Mercalli Intensity scale (MM) along with the generation of an ESI-2007 shake map, which is solely based on site-specific ESI-2007 intensity values. According to the ESI-2007 scale, the epicentral intensity I0=X is assessed. This is two degrees higher than the intensity of the PEIS, and three degrees higher than the modified MM intensity provided by the United States Geological Survey (USGS). The intensity difference may also be due to the lack of suitable observations of building damage data in this sparsely populated region of the Philippines. Comparison of the ShakeMap that was constructed using the ESI-2007 intensities with the PHIVOLCS and USGS ShakeMap suggests that the instrumental or structural damage-based intensity maps underestimate the seismic intensity for the 2012 Negros Oriental earthquake. The ESI-2007 ShakeMap presented in this work is pertinent for the assessment of future seismic risk associated with other earthquake generators in the vicinity of the islands of Negros and Cebu. It can be integrated with the PEIS or MM intensity scale to improve disaster management and planning, post-earthquake recovery efforts, and damage estimation.

Environmental effects following a seismic sequence: the 2019 Cotabato—Davao del Sur (Philippines) earthquakes

In the period of October–December 2019, the Cotabato–Davao del Sur region (Philippines) was hit by a seismic sequence comprising four earthquakes with magnitude MW > 6.0 (EQ1-4; max magnitude MW 6.8). The earthquakes triggered widespread environmental effects, including landslides and liquefaction features. We documented such effects by means of field surveys, which we supplemented with landslide mapping from satellite images. Field surveys allowed us to gather information on 43 points after EQ1, 202 points after EQs2–3 and 87 points after EQ4. Additionally, we built a multi-temporal inventory of landslides from remote sensing, comprising 190 slope movements triggered by EQ1, 4737 after EQs2–3, and 5666 at the end of the sequence. We assigned an intensity value to each environmental effect using the environmental seismic intensity (ESI-07) scale. Our preferred estimates of ESI-07 epicentral intensity are VIII for the first earthquake and IX at the end of the sequence, which is in broad agreement with other events of similar magnitude globally. This study, which is the first case of the application of the ESI-07 scale to a seismic sequence in the Philippines, shows that repeated documentation of environmental damage and the evaluation of the progression through time may be useful for providing input data for derivative products, such as susceptibility assessment, evaluation of residual risk or investigation of the role played by ground shaking and by other mechanisms able to trigger environmental effects.

Earthquake-triggered landslides and Environmental Seismic Intensity: insights from the 2018 Papua New Guinea earthquake (M w 7.5)

Earthquake-triggered landslides and Environmental Seismic Intensity: insights from the 2018 Papua New Guinea earthquake (M _w 7.5)

28th September 2018 Mw 7.5 Sulawesi Supershear Earthquake, Indonesia: Ground effects and macroseismic intensity estimation using ESI-2007 scale

The 28th September 2018 Sulawesi Supershear earthquake (MW 7.5) was one of the deadliest earthquakes in the recent history of Indonesia causing ∼4000 causalities. The earthquake caused a ∼ 177 km long surface rupture along the Palu-Karo fault. Apart from surface rupture, the earthquake caused extensive earthquake environmental effects (EEEs) around the Palu-Donggala area of Central Sulawesi, Indonesia, which includes tsunami, coastal landslide, liquefaction, ground cracks and more than 7300 landslides in hilly areas. Initial post-event analysis and reports assigned a Modified Mercalli Intensity (MMI) of VII to VIII in Palu City and the surrounding area. Building damage and ground effects caused by the earthquake suggested that seismic intensity was understated. Here we applied the EEEs information from field survey data, published reports, and remote sensing tools to determine macroseismic intensity using the Environmental Seismic Intensity (ESI-07) Scale. The ESI-07 intensity derived from the ground effects suggests the maximum intensity of X-XI, which is 3–4° higher than the traditional intensity estimated by the United States Geological Survey (USGS) and the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG). ShakeMaps were generated considering the ESI-07 values. The ShakeMap was compared with the instrumentally derived ShakeMap for the Palu earthquake, which proves that the ShakeMap prepared from the instrumental data or structural damage data is underrated. We argue that proper documentation of the EEEs is necessary for such damaging earthquakes for future earthquake hazard mapping and planning in the study area and other earthquakes in Indonesia. In addition, this will help in defining the on-fault and off-fault damage zone towards reducing the seismic risk of the Palu Donggala area.

The earthquake environmental effects (EEEs) of the 6th February 2018, Hualien earthquake (Mw=6.4): A contribution to the seismic hazard estimation in the epicentral area

The macroseismic intensity of the February 6, 2018, Mw 6.4, Hualien earthquake, which caused extensive damage around the Hualien area of eastern Taiwan is reassessed using the Environmental Seismic Intensity (ESI-07) scale. We compiled data on earthquake environmental effects (EEEs) caused by the 2018 Hualien earthquake, which includes surface ruptures, ground cracks, liquefaction, and occasional landslides, and estimated the epicentral intensity (I0) as well as site-specific intensities. We found that the ESI-07 epicentral intensity of the Hualien quake in 2018 is IX. We note that the epicentral area of the 2018 Hualien earthquake was the mesoseismal area of the October 22, 1951, (Mw 6.6) Hualien earthquake, as reported in primary contemporary sources and historical earthquake catalogs. The 1951 Hualien earthquakes also caused prominent surface ruptures, liquefaction, and ground cracks. Consequently, we reassess the macroseismic intensities of this historical seismic event and compare it to the Hualien earthquake in 2018. The comparison suggests similar epicentral intensities for the two earthquakes (IX and X ESI-07). Moreover, we conducted a systematic comparison between intensity obtained using different scales which revealed the differences of two to three degrees between the ESI-07 and traditional intensity scales. This result reconfirms the significance of documentation and recording of earthquake environmental effects to make intensity assessments for modern seismic events consistent with the historical earthquake records. Moreover, a re-evaluation of historical earthquake intensity in eastern Taiwan could be performed in order to update the seismic hazard map. Application of the ESI-07 intensity scale of recent and historical earthquakes will be helpful in post-earthquake recovery efforts for a future earthquake. The prepared ShakeMaps from the ESI-07 values suggests completely different shapes to the previously generated ShakeMaps considering the peak ground acceleration or peak ground velocity. It suggests that the ShakeMaps prepared from the earthquake environmental effects can be complemented with the instrumental based intensity map to have a better seismic hazard prediction and future land use planning for the region.

Landslides triggered by the 2015 Mw 6.0 Sabah (Malaysia) earthquake: inventory and ESI-07 intensity assignment

Abstract. On 4 June 2015, a Mw 6.0 earthquake occurred in the Sabah region (Malaysia), triggering widespread landslides along the slopes of Mt. Kinabalu. Despite the moderate magnitude, the Sabah earthquake was very efficient in triggering landslides: here I provide an inventory containing 5198 slope movements, mapped in an 810 km2 wide area. I investigate earthquake intensity using the Environmental Seismic Intensity (ESI-07) scale, which is a macroseismic scale based exclusively on earthquake environmental effects. The epicentral ESI-07 intensity is assessed at IX, considering the dimension of the area affected by secondary effects; such figure agrees well with a dataset of global earthquakes. I estimate the volume of individual landslides using area–volume scaling laws; then, I assign an ESI-07 intensity to each mapped landslide. I document that the selection of a given area–volume relation has a minor influence on the ESI-07 assignment. Then, I compare ESI-07 values to landslide density and areal percentage on a 1 km2 grid; such parameters are widely adopted in the description of earthquake-triggered landslide inventories. I argue that their integration with the ESI-07 scale may provide an effective way to compare earthquake damage on a variety of spatial and temporal scales. The methodological workflow illustrated here is useful in joining the scientific communities dealing with the development of earthquake-triggered landslide inventories and with ESI-07 assignment; I believe this effort is beneficial for both communities.

Fifteen years of Environmental Seismic Intensity (ESI-07) scale: Dataset compilation and insights from empirical regressions

The Environmental Seismic Intensity scale (ESI-07), published 15 years ago under the umbrella of INQUA (International Union for Quaternary Research), is solely based on earthquake effects on the natural environment. ESI-07 provides complementary information with respect to other macroseismic scales, in particular those stemming from the original Mercalli scale, which are mainly based on effects on manmade structures. We collect information on 157 earthquakes, occurred between 300 AD and 2020, that have been studied using the ESI-07 scale. The ESI-07 epicentral intensity can be assigned based on linear or areal features (e.g., length of surface rupture, area affected by environmental effects); this value is generally in good agreement, or slightly larger, than estimates provided using other macroseismic scales. Higher discrepancies are found for earthquakes with ESI-07 epicentral intensity above X, where other scales tend to saturate, as expected based on the original definition of the Mercalli-family intensity scales. We develop scaling relations among ESI-07 epicentral intensity and moment magnitude, surface rupture length and affected area. After critically evaluating the scientific literature, we argue that the ESI-07 reached its original goals and proved to be particularly useful for the documentation of earthquake damage i) in remote regions, ii) in the case of strong events, where other scales saturate, and iii) in the region closer to the epicenter. Finally, we identify gaps where to focus future efforts, such as the integration of remote sensed datasets in ESI-07 assignment and the refinement of empirical regressions.

Environmental effects caused by the Mw 8.2, September 8, 2017, and Mw 7.4, June 23, 2020, Chiapas-Oaxaca (Mexico) subduction events: Comparison of large intraslab and interface earthquakes

Earthquake Environmental Effects (EEEs) such as surface faulting, landslides, liquefaction and tsunamis are widely distributed following strong seismic events and may account for a significant part of the overall damage. Here, we investigate EEEs generated by two earthquakes with different source parameters, both occurring along the Mexican subduction zone: the Sept. 8, 2017, Mw 8.2, moderate depth, normal fault, intraslab event; and the June 23, 2020, Mw 7.0, shallow depth, thrust fault, interface event. We document the EEEs for each event, assign an intensity value using the Environmental Seismic Intensity (ESI-2007) scale, and derive the macroseismic fields. Finally, we compute the attenuation of intensity with distance and we compare it with other subduction zone earthquakes worldwide, demonstrating the repeatability of EEEs. This work represents the first application of the ESI-2007 scale to an intraslab earthquake and documents its wide applicability in different seismotectonic settings. We argue that EEEs provide useful information that should not be neglected in seismic hazard assessment procedures.

Primary and Secondary Environmental Effects Triggered by the 30 October 2020, Mw = 7.0, Samos (Eastern Aegean Sea, Greece) Earthquake Based on Post-Event Field Surveys and InSAR Analysis

On 30 October 2020, an Mw = 7.0 earthquake struck the eastern Aegean Sea. It triggered earthquake environmental effects (EEEs) on Samos Island detected by field surveys, relevant questionnaires, and Interferometric Synthetic Aperture Radar (InSAR) analysis. The primary EEEs detected in the field comprise coseismic uplift imprinted on rocky coasts and port facilities around Samos and coseismic surface ruptures in northern Samos. The secondary EEEs were mainly observed in northern Samos and include slope failures, liquefaction, hydrological anomalies, and ground cracks. With the contribution of the InSAR, subsidence was detected and slope movements were also identified in inaccessible areas. Moreover, the type of the surface deformation detected by InSAR is qualitatively identical to field observations. As regards the EEE distribution, effects were generated in all fault blocks. By applying the Environmental Seismic Intensity (ESI-07) scale, the maximum intensities were observed in northern Samos. Based on the results from the applied methods, it is suggested that the northern and northwestern parts of Samos constitute an almost 30-km-long coseismic deformation zone characterized by extensive primary and secondary EEEs. The surface projection of the causative offshore northern Samos fault points to this zone, indicating a depth–surface connection and revealing a significant role in the rupture propagation.

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.

Testing the Environmental Seismic Intensity Scale on Data Derived from the Earthquakes of 1626, 1759, 1819, and 1904 in Fennoscandia, Northern Europe

Earthquake environmental effects (EEEs) were compiled for the earthquakes of 1626, 1759, 1819, and 1904 in the Fennoscandian Peninsula, northern Europe. The principal source of information was the contemporary newspaper press. Macroseismic questionnaires collected in 1759 and 1904 were also consulted. We prepared maps showing newly discovered EEEs together with previously known EEEs and analyzed their spatial distribution. We assigned intensities based on the 2007 Environmental Seismic Intensity (ESI) scale to 27 selected localities and compared them to intensities assigned based on the 1998 European Macroseismic Scale. While the overall agreement between the scales is good, intensities may remain uncertain due to the sparsity of written documentation. The collected data sets are most probably incomplete but still show that EEEs are not unprecedented cases in the target region. The findings include landslides and rockfalls as well as cascade effects with a risk potential and widespread water movements up to long distances. The winter earthquake of 1759 cracked ice over a large area. This investigation demonstrates that the ESI scale also has practical importance for regions with infrequent EEEs.

Intensity Reassessment of the 2017 Pohang Earthquake Mw = 5.4 (South Korea) Using ESI-07 Scale

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’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 1–2-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.

Reappraisal of the 1863 Huércal-Overa Earthquake (Betic Cordillera, SE Spain) by the Analysis of ESI-07 Environmental Effects and Building Oriented Damage

This work reviews the 1863 Huércal-Overa earthquake (VI-VII EMS) based on the environmental seismic intensity scale (ESI-07) and oriented archaeoseismological building damage. The performed analysis identifies 23 environmental effects (EEEs) and 11 archaeoseismological effects (EAEs), completing a total of 34 intensity data-points within the intensity zone ≥ VI EMS. The new ESI intensity data quintuplicate the previous intensity data-points ≥ VI EMS (five localities) for this event. Sixteen of the identified EEEs indicate the occurrence of intensity VII-VIII within the Almanzora valley, south of Huércal-Overa, over an area of ca. 12–15 km2. Anomalies in water bodies, slope movements, hydrogeological anomalies, ground cracking, and other effects (gas emissions, tree shaking) are the more diagnostic EEEs—with one of them indicating a local maximum intensity of VIII-IX ESI-07 (Alboraija lake). Environmental earthquake damage of intensity ≥ VI covers an area of c. 100 km2, compatible with a VIII ESI intensity event. The spatial distribution of EEEs and EAEs indicates that the zone of Almanzora River Gorge, which was depopulated during the earthquake epoch, was the epicentral area, and compatible with seismotectonic data from active shallow blind thrusting beneath the Almagro Range. The use of ESI data in nearly unpopulated areas help to fill gaps between damaged localities (EMS data) multiplying intensity data-points, providing a better definition of the intensity zones and offering a geological basis to look for suspect seismic sources.

New Perspectives in the Definition/Evaluation of Seismic Hazard through Analysis of the Environmental Effects Induced by Earthquakes

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 1976 Guatemala Earthquake: ESI Scale and Probabilistic/Deterministic Seismic Hazard Analysis Approaches

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.

Evaluation of environmental seismic intensities of all known historical and recent earthquakes felt in Zakynthos Island, Greece using the Environmental Seismic Intensity (ESI 2007) scale

The complete and detailed knowledge of the historical earthquakes, the past earthquake environmental effects (EEE) and the respective seismic intensities has become significant in recent years due to the fact that among others it serves as a valuable tool for revealing and highlighting sites of significant earthquake-related hazards. Many efforts have been made to record the EEE of individual recent earthquakes and evaluate their seismic intensity based on the Environmental Seismic Intensity 2007 scale (ESI 2007) in Greece and around the world. But fewer studies have focused on the complete seismic history including historical and recent earthquakes of an area and the respective intensities based on the induced EEE. The Central Ionian Islands (Western Greece) and especially Zakynthos Island are considered appropriate for the development of this approach. The complete history of earthquakes with destructive impact on Zakynthos from 1513 to present is presented. Emphasis is given on EEE, while the respective ESI 2007 intensities are assigned. Based on the EEE's distribution on the affected fault blocks, it is concluded that eastern Zakynthos has been affected more often and severely by earthquakes. This selective distribution is attributed to the neotectonic setting of Zakynthos. The recording of the EEE over the past five centuries and the study of possible correlation with the seismotectonic structure of the affected area could be used as a basic guide for the reduction of the future seismic risk and the risk from EEE through effective land-use planning and preparedness in earthquake-prone areas.

Seismotectonic analyses of Karachi Arc, Southern Kirthar Fold Belt, Pakistan

In this study geomorphological and seismotectonic analyses were carried out in Karachi arc area, southernPakistan to locate relatively safe areas from earthquakes disasters. Karachi arc is the southern extremity of the Kirtharmountain chain that occupies a major part of southern Pakistan and is comprised of a number of narrow, elongatedmountain ranges, i.e. Laki, Kirthar, Khud, Pab and Mor ranges. Based on geomorphological and seismotectonicanalyses Karachi arc area has been divided into three parts. These parts are northern, frontal and southern part. Thenorthern part of Karachi arc is seismically active where minor to moderate (3-5.9Mb) earthquakes occurred. Somebasement structures in Sehwan area seem to be still active and affected by the present-day transpressional stress field.The frontal part of Karachi arc is also active as manifested by the existence of active faults in Jhimpir, Surjan andMeting areas. These embryonic structures in the eastern part of the Arc are indicators of active deformation of Karachiarc. Presently the active deformation is taking place in frontal and northern parts of the arc, while the southern part thathas experienced deformation prior to Quaternary time is inactive and is relatively stable geoblock. The instrumental andhistoric seismicity record of the adjoining areas of Karachi arc show that the area has experienced light to moderateseismic events (4-5.9) with occasional occurrence of strong and major earthquakes. Any major or strong event in Katchrift zone, Makran subduction zone and Ornach-Nal fault zone may cause intensity of VII to VIII in Karachi arc area aswell as Karachi city of environmental seismic intensity scale 2007.

Seismotectonic analyses of Karachi Arc, Southern Kirthar Fold Belt, Pakistan

In this study geomorphological and seismotectonic analyses were carried out in Karachi arc area, southernPakistan to locate relatively safe areas from earthquakes disasters. Karachi arc is the southern extremity of the Kirtharmountain chain that occupies a major part of southern Pakistan and is comprised of a number of narrow, elongatedmountain ranges, i.e. Laki, Kirthar, Khud, Pab and Mor ranges. Based on geomorphological and seismotectonicanalyses Karachi arc area has been divided into three parts. These parts are northern, frontal and southern part. Thenorthern part of Karachi arc is seismically active where minor to moderate (3-5.9Mb) earthquakes occurred. Somebasement structures in Sehwan area seem to be still active and affected by the present-day transpressional stress field.The frontal part of Karachi arc is also active as manifested by the existence of active faults in Jhimpir, Surjan andMeting areas. These embryonic structures in the eastern part of the Arc are indicators of active deformation of Karachiarc. Presently the active deformation is taking place in frontal and northern parts of the arc, while the southern part thathas experienced deformation prior to Quaternary time is inactive and is relatively stable geoblock. The instrumental andhistoric seismicity record of the adjoining areas of Karachi arc show that the area has experienced light to moderateseismic events (4-5.9) with occasional occurrence of strong and major earthquakes. Any major or strong event in Katchrift zone, Makran subduction zone and Ornach-Nal fault zone may cause intensity of VII to VIII in Karachi arc area aswell as Karachi city of environmental seismic intensity scale 2007.

Review of geological and seismotectonic investigations related to 1998 Mw5.6 and 2004 Mw5.2 earthquakes in Krn Mountains

A review of geological and seismotectonic investigations conducted in the two decades after the 12 April 1998 earthquake in Krn Mountains, according to its magnitude the strongest earthquake in Slovenia in the 20th century, is given. Many of these studies have wider scientific meaning than expected from the size of the earthquake. This was the first case in Slovenia that a strong earthquake was undoubtedly related to a particular fault. Seismotectonic studies of seismogenic Ravne fault revealed that it is an actively propagating strike-slip fault growing by interaction of individual right stepping fault segments and breaching of local transtensional step-over zones. Airborne laser scanning (LiDAR) of Idrija and Ravne faults, which resulted in high resolution bare earth digital elevation model, was in 2005 for the first time used to study surface expression of an active fault in Europe. Among the primary characteristics of the 1998 earthquake were extensive environmental effects expressed mainly as massive rockfalls. They were systematically documented and evaluated for intensity assessment using European Macroseismic Scale (EMS-98) and Environmental Seismic Intensity (ESI) scale introduced in 2007, because application of the data on damage to buildings was limited in sparsely populated high mountains epicentral area. These studies were pioneering due to novelty of both intensity scales, indicating their strong points and weaknesses. Large variations in damage to buildings in the upper Soča valley at similar epicentral distances pointed to strong site effects due to very heterogeneous glacial and fluvial deposits in sedimentary basins and valleys. Therefore, different seismic microzonation maps were prepared to evaluate the influence of soft sediments on seismic ground motion. Conducted studies fostered development of several earthquake geology research methods in Slovenia as tectonic geomorphology, evaluation of environmental seismic effects and seismotectonics. They had positive impact also on the university education in the fields of geophysics, seismology and structural geology.

Catalogue of the Geological Effects of Earthquakes in Spain Based on the ESI-07 Macroseismic Scale: A New Database for Seismic Hazard Analysis

This paper summarizes the content and scope of the “Catalogue of Earthquake Geological Effects in Spain”. The catalogue has been published by the Geological Survey of Spain (IGME) and constitutes the first official publication (in Spain) on seismic hazard containing geological information. The catalogue gathers the 51 stronger earthquakes that have occurred in Spain since the Neolithic period to the present and classifies earthquakes with geological or archaeological seismic records in paleoseismic, ancient, historical and instrumental earthquakes. The catalogue offers a variety of parametric information, quality indexes (Qe, Qi, Qg), and Environmental Seismic Intensity Scale (ESI-07) based description of environmental damage structured in individual “event files”. Sixteen of the 51 catalogued events present full information files (full event files), with individualized analyses of the geological and geoarchaeological data as well as graphic information with hybrid ESI-EMS intensity maps, ShakeMaps (seismic scenarios) and complementary kmz files (Google Earth) for each of the sixteen selected earthquakes; among which is the well-known AD 1755 Lisbon earthquake-tsunami. These selected earthquakes present individual environmental earthquake effects (EEE) or earthquake archaeoseismological effects (EAE) files for each catalogued effect containing specific site geo-information and graphic data (photos, graphs, maps, etc.). The second edition of the catalogue record 1027 EEEs and 187 EAEs, of which 322 effects have individual files.