Horea Mircea Ioan Sandi, the most prominent Romanian researcher in Seismology and Earthquake Engineering passed away on 4 December 2020, a few weeks before his 89th birthday.He studied at the Technical University of Civil Engineering in Bucharest, during 1950–1955, and at the Faculty of Mathematics of the University of Bucharest, during 1950–1954. He received his Ph.D. with the doctoral thesis “Contributions

Observational seismology in Europe is firmly rooted in national and regional observatories in charge of managing more than 100 permanent seismic networks and more than 200 past and present temporary deployments. Primarily driven by governmental mandates to detect local seismicity and provide earthquake information to civil protection agencies and the general public, this monitoring effort also results

Although Norway has had an open data policy for seismological data for a long time, access to a good portion of the data required the use of nonstandard tools. This changed with the establishment of a dedicated European Integrated Data Archive (EIDA) node that is operated jointly by the UiB (University of Bergen)‐NORSAR. This now gives access to 139 stations and currently 12.1 Tb of data. The archive

This contribution describes the development of Norwegian Seismic Array (NORSAR), from its origin 50 yr ago as a project for installing a single seismic array in southern Norway to a seismological research institute operating a network of six arrays and 14 three‐component stations located in Norway and Antarctica. In addition, we document the different instrumentations from narrowband, mostly short‐period

The correct orientation of seismic sensors is critical for studies such as full moment tensor inversion, receiver function analysis, and shear‐wave splitting. Therefore, the orientation of horizontal components needs to be checked and verified systematically. This study relies on two different waveform‐based approaches, to assess the sensor orientations of the broadband network of the Kandilli Observatory

The complex tectonic setup of eastern Europe—resulting in strong spatial variations of the local seismic hazard—caused relevant institutions of neighboring countries to form a research cooperation to ease seismological research cooperations across borders.Here, we briefly introduce the original and new Central and Eastern Europe Earthquake Research Network (⁠CE3RN⁠) parties, with a synthesis of the

New data acquisition techniques are generating data at much finer temporal and spatial resolution, compared to traditional seismic experiments. This is a challenge for data centers and users. As the amount of data potentially flowing into data centers increases by one or two orders of magnitude, data management challenges are found throughout all stages of the data flow.The Incorporated Research Institutions

Portugal, located in the southwest region of the Eurasian plate, has been affected by several destructive earthquakes throughout its history, the most well‐known being the 1755 Great Lisbon earthquake. The seismicity of the territory, both in the mainland and in the Azores and Madeira islands, has prompted the continuous development of seismic monitoring, from the first known macroseismic inquiry,

As the earliest institute in Turkey dedicated to locating, recording, and archiving earthquakes in the region, the Kandilli Observatory and Earthquake Research Institute (KOERI) has a long history in seismic observation, which dates back to the installation of its first seismometers soon after the devastating Istanbul earthquake of 10 July 1894. For over a century, since the deployment of its first

We present an overview of the seismic networks, products, and services in Finland, northern Europe, and the challenges and opportunities associated with the unique combination of prevailing crystalline bedrock, low natural intraplate seismic background activity, and a high level of anthropogenic seismicity. We introduce national and local seismic networks, explain the databases, analysis tools, and

The SWATH‐D experiment involved the deployment of a dense temporary broadband seismic network in the Eastern Alps. Its primary purpose was enhanced seismic imaging of the crust and crust–mantle transition, as well as improved constraints on local event locations and focal mechanisms in a complex part of the Alpine orogen. The study region is a key area of the Alps, where European crust in the north

The GEOFON program consists of a global seismic network, a seismological data center, and a global earthquake monitoring system. The seismic network has regional focus in Europe and North Africa as well as throughout the Indian Ocean, but it operates stations on all continents, including Greenland on the North American continental plate and Antarctica. The data center provides real‐time seismic data

In recent years, the French seismological, geodetic, and gravimetric community has been structured within Réseau Sismologique et géodésique Français (RESIF) (French seismological and geodetic network). In addition to instrumental developments, RESIF has structured the work on French seismicity (metropolitan and overseas) within the RESIF transverse seismicity action (ATS). The purpose of this article

Strong ground motion records and free open access to strong‐motion data repositories are fundamental inputs to seismology, engineering seismology, soil dynamics, and earthquake engineering science and practice. This article presents the current status and outlook of the Observatories and Research Facilities for European Seismology (ORFEUS) coordinated strong‐motion seismology services, namely the rapid

The Istituto Nazionale di Geofisica e Vulcanologia (INGV) is an Italian research institution with focus on earth sciences. Moreover, the INGV is the operational center for seismic surveillance and earthquake monitoring in Italy and is a part of the civil protection system as a center of expertise on seismic, volcanic, and tsunami risks.INGV operates the Italian National Seismic Network and other networks

The National Observatory of Athens data center for the European Integrated Data Archive (EIDA@NOA) is the national and regional node that supports International Federation of Digital Seismograph Networks and related webservices for seismic waveform data coming from the southeastern Mediterranean and the Balkans. At present, it serves data from eight permanent broadband and strong‐motion networks from

The aim of this article is to analyze the background, current status, and outlook of seismic monitoring products and services in Bulgaria, Moldova, Romania, and Ukraine. These countries manage seismic networks that contribute to the European Integrated Data Archive node in the framework of the Observatories and Research Facilities for European Seismology, which represents a collaborative effort in

In this article, we describe the infrastructure developed and managed by the Italian National Institute of Oceanography and Applied Geophysics – OGS for the seismological and geodetic monitoring of northeastern Italy. The infrastructure was constituted in response to the ML 6.4 Friuli destructive earthquake of 1976, with the main mandate of supporting civil protection emergency activities.The OGS monitoring

High‐quality and open‐access seismic data are of great importance for both research and increasing public awareness of actual seismic hazards and risks. We present four seismic networks that currently operate in Poland: the backbone Polish Seismological Network (PLSN), which monitors natural teleseismic events as well as regional events from Poland, and three networks that mainly serve the monitoring

The Orfeus European Integrated Data Archive (EIDA) provides a federated approach to the dissemination of seismological waveform data and ensures access to 12 regional seismological data centers—the EIDA nodes. The Istituto Nazionale di Geofisica e Vulcanologia (INGV) is one of the founding partners of this EIDA federation and manages the EIDA data distribution node in Italy. INGV has actively managed

The Istituto Nazionale di Geofisica e Vulcanologia (INGV) is in charge of earthquake monitoring and surveillance in the Italian territory as a part of the civil protection system. Technological improvements in the last years were taken into account for developing new protocols and software to upgrade all the procedures in the monitoring centers. Real‐time earthquake evaluation consists of phase picks

The Swedish National Seismic Network (SNSN) was modernized and rapidly expanded during the period 1998–2012. The network currently operates 68 permanent seismic stations, all with broadband instruments supplying real‐time continuous data at 100 samples per second. Continuous data from 10 stations are shared with the international community via Orfeus, and approximately 10 stations of their individual

We present Rapid Assessment of MOmeNt and Energy Service (RAMONES), a service for disseminating through a web interface, the estimates of seismic moment (⁠M0⁠) and radiated energy (⁠ER⁠) for earthquakes occurring in central Italy with local magnitudes above 1.7. The service is based on a fully‐automatic procedure developed for downloading and processing open seismological data from the European Integrated

In the northern Alpine foreland of southwest Germany, continuous microseismic activity is observed, with the potential for strong earthquakes up to magnitude 5 or even 6+. The StressTransfer network is designed to complement the existing seismic networks in three defined areas: the southern Upper Rhine graben, the Albstadt shear zone, and the central Molasse basin around the town of Bad Saulgau. The

The European Integrated Data Archive (EIDA) is the infrastructure that provides access to the seismic‐waveform archives collected by European agencies. This distributed system is managed by Observatories and Research Facilities for European Seismology. EIDA provides seamless access to seismic data from 12 data archives across Europe by means of standard services, exposing data on behalf of hundreds

The Italian Tsunami Alert Center based at the Istituto Nazionale di Geofisica e Vulcanologia (CAT‐INGV) has been monitoring the Mediterranean seismicity in the past 8 yr to get fast and reliable information for seismically induced tsunami warnings. CAT‐INGV is a tsunami service provider in charge of monitoring the seismicity of the Mediterranean Sea and of alerting Intergovernmental Oceanographic Commission

The Sicily Channel, situated on the leading edge of the African plate as it collides with Europe, presents a range of interesting and complex tectonic processes that have developed in response to various regional stress fields. The characterization and interpretation of the seismic activity, however, still presents a challenge. The Maltese islands, lying approximately 100 km to the south of Sicily

The Résif project, which started in 2008, aims at gathering under a common research infrastructure the French seismological, Global Navigation Satellite Systems and gravimeter permanent networks, as well as the mobile instrument pools. A central part of Résif is its seismological information system, Système d'Information de Résif (Résif‐SI) (started in 2012), which is in charge of collecting, validating

Germany has a long history in seismic instrumentation. The installation of the first station sites was initiated in those regions with seismic activity. Later on, with an increasing need for seismic hazard assessment, seismological state services were established over the course of several decades, using heterogeneous technology. In parallel, scientific research and international cooperation projects

On 15 May 2020 an Mww 6.5 earthquake occurred beneath the Monte Cristo Range in the Mina Deflection region of western Nevada. Rapid deployment of eight temporary seismic stations enabled detailed analysis of its productive and slowly decaying aftershock sequence (⁠p=0.8⁠), which included ∼18,000 autodetected events in 3.5 months. Double‐difference, waveform‐based relative relocation of 16,714 earthquakes

On 23 June 2020, a large (⁠Mw 7.4) interplate thrust earthquake struck near the town of La Crucecita in the state of Oaxaca in southern Mexico, following a 55‐yr interseismic period. A seismic source model is well constrained by teleseismic waveforms, static Global Positioning System offsets, and tsunami data, suggesting that the earthquake occurred on the slab interface at a dip of ∼23°⁠, with a narrow

On 23 June 2020, an Mw 7.4 earthquake struck offshore Oaxaca, Mexico, providing a unique opportunity to understand the seismogenic tectonics of the Mexican subduction zone. In this study, near‐field coseismic deformation caused by the event was retrieved from Global Positioning System (GPS) observations and Interferometric Synthetic Aperture Radar (InSAR) measurements. Given static geodetic measurements

On 4 January 2020, an ML 3.5 earthquake occurred in the Pearl River Estuary (PRE) and was felt at a distance of more than 200 km. According to the China Earthquake Networks Center, this event has been the only M>3 earthquake within the PRE since 1900. The Guangdong–Hong Kong–Macau Bay Area (GHMBA) surrounding the PRE is one of China’s most critical financial circles, and coastal earthquake hazard has

Foreshocks in the form of microseismicity are among the most powerful tools to study the physical processes that occur before main earthquakes. However, their detection and precise characterization is still sparse, especially for small‐to‐moderate‐size earthquakes (⁠Mw<6⁠). We present here a detailed foreshock analysis for the 7 November 2019, Balsorano, Italy, normal fault earthquake (⁠Mw 4.4). To

Foreshock activity sometimes precedes large earthquakes, but how foreshocks relate to mainshock nucleation is still unclear with limited case studies existing. One way to further the understanding of the foreshock occurrence mechanism is to maximize the resolution of the foreshock characteristics by waveform‐based earthquake detection and location. Here, we apply the match and locate method to scan

Seismological methods have been widely used to construct subsurface images in urban areas, for both seismological and engineering purposes. However, it remains a challenge to continuously operate a dense array in cities for high‐resolution 4D imaging. In this study, we utilized distributed acoustic sensing (DAS) and a 5.2 km long, L‐shaped, telecom, fiber‐optic cable to record the wavefield from a

Rapid information on fault rupture geometry is critically important to assess damage and fatalities in large earthquakes and is strongly needed to coordinate rapid rescue efforts if and where necessary. Many countries around the world, however, cannot afford to operate dense seismic networks required to rapidly determine rupture geometry. In this feasibility study, we investigate if crowd-sourced felt

The peak inelastic displacement of single‐degree‐of‐freedom bilinear systems (⁠Sdi⁠) is an effective intensity measure linking ground‐motion features to the inelastic response and subsequent structural and nonstructural damage of engineered systems. This study develops a region‐specific ground‐motion model for Sdi considering source, path, and site effects and explicitly accounting for the spatial

The primary aim of this study is to use microseismic events to perform a stress inversion, which has often been excluded in past studies. New insights on the seismogenic structures and stress state in northeastern Taiwan can be acquired by applying 3D velocity structure relocation, raytracing techniques, and stress inversion methods to an entire database, which permits objective and reliable selection

An effective approach was developed for identifying and correcting ocean‐bottom seismometer (OBS) time errors through improving ambient noise cross‐correlation function (NCCF) analysis and combination with other methods. Significant improvements were illustrated through analyzing data from a passive‐source seismic experiment in the southwestern sub‐basin of the South China Sea. A novel method was first

We propose an optimization method for applying the seismic‐wave gradiometry (SWG) method to a dense seismic station network consisting of nonuniformly distributed seismographs. As a nonuniformly distributed station array, we consider the station layout of the Metropolitan Seismic Observation Network (MeSO‐net) operated in and around the Tokyo metropolitan area, Japan. In this study, thereby, we numerically

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

In anticipation of future spacecraft missions to icy ocean worlds, the Seismometer to Investigate Ice and Ocean Structure (SIIOS) was funded by National Aeronautics and Space Administration, to prepare for seismologic investigations of these worlds. During the summer of 2018, the SIIOS team deployed a seismic experiment on the Greenland ice sheet situated, approximately, 80 km north of Qaanaaq, Greenland

The NOANET network is a continuously operating high‐rate Global Navigation Satellite System (GNSS) network in Greece whose primary role is to enhance and support geophysical research employing GNSS data. This network is operated by the Institute of Geodynamics of the National Observatory of Athens and currently (September 2020) consists of 26 stations, most of which are located close to major seismogenic

We present a Hellenic database of intensity measures from uniformly processed strong ground motion recordings, together with metadata on earthquake source attributes and recording site conditions. The database consists of information from 471 earthquakes between 1973 and 2015 that produced 2993 usable recordings from 333 sites. A key element of this work is a unified presentation of data from two major

This article identifies deficiencies in the article of Bernauer et al. (2020) in performing and describing shake table and numerical (synthetic) testing of newly designed seismic instruments for recording complex translational and rotational motion. In my opinion, this is a result from a deficiency in referencing previously published peer‐reviewed papers in this area. I also disagree with Bernauer

We fully acknowledge the work of Vladimir Graizer in the field of seismic strong‐motion recording and his detailed analysis of the interaction between tilt and inertial sensors which can certainly be referenced in countless publications. We also appreciate very much Graizer’s initiative to open a discussion on our article which will certainly increase the article’s visibility and even more highlights

After the publication of Pinet et al. (2020), it was brought to the attention of the authors that Normandeau et al. (2015) also speculated about the possibility of Quaternary fault motion along the Tadoussac segment of the St‐Laurent fault. Normandeau et al. (2015) based their interpretation on the absence of fan‐like deposits at the base of the canyons located in the footwall of the fault. Pinet and

SSA announced the election results from the 8 January 2021 election, conducted by YesElections, formerly known as Election America.Three new members will join the board for 3 yr terms, and one board member was re‐elected to a second term: Karen Fischer, Brown UniversityZhigang Peng, Georgia Institute of TechnologyXyoli Pérez‐Campos, Universidad Nacional Autónoma de MéxicoCarl Tape, University of Alaska

Donald V. Helmberger, Ph.D. and Smits Family Professor of Geophysics Emeritus at Caltech, and one of the most impactful seismologists to have lived, died on 13 August 2020. Don was born 23 January 1938, the youngest child of 13, in the small rural town of Perham, Minnesota. He completed his bachelor’s degree in physics at the University of Minnesota in 1961. That summer, he participated in a cruise

Seismologists are eagerly seeking new and preferably low‐cost ways to map and track changes in the complex structure of the top few kilometers of the crust. By understanding it better, they can build on what is known regarding important, practical issues. These include telling us whether imminent earthquakes and volcanic eruptions are generating telltale underground signs of hazard, about mitigation

The Intermountain West region of the United States extends from the eastern margin of the Sierra Nevada and Cascade Mountains in the west to the Rocky Mountains in the east. The region is characterized by dextral shear along the eastern margin of the Sierra Nevada and nearly east–west extension in the Basin and Range. This region experienced four significant earthquake sequences in the first half of

We present the application of a backprojection method for imaging the detailed rupture of the 2020 Mw 5.5 Magna, Utah, earthquake. This is the first time that this method is applied to an earthquake smaller than Mw 6 in a local scale using a dense strong‐motion network. The 2020 Magna earthquake occurred in a very well instrumented area, the Salt Lake valley, with tens of strong‐motion seismic stations

The 15 May 2020, M 6.5 Monte Cristo Range, Nevada earthquake (MCE) occurred inside the footprint of the semicontinuous MAGNET and continuous Network of the Americas Global Positioning System (GPS) networks, which provide precise geodetic coverage in the western Great basin. The event occurred in the White Mountain seismic gap between twentieth century events in the eastern central Walker Lane, on an

We report on the tectonic framework, seismicity, and aftershock monitoring efforts related to the 31 March 2020 Mw 6.5 Stanley, Idaho, earthquake. The earthquake sequence has produced both strike‐slip and dip‐slip motion, with minimal surface displacement or damage. The earthquake occurred at the northern limits of the Sawtooth normal fault. This fault separates the Centennial tectonic belt, a zone

The 2020 Mw 5.8 Lone Pine earthquake, the largest earthquake on the Owens Valley fault zone, eastern California, since the nineteenth century, ruptured an extensional stepover in that fault. Owens Valley separates two normal‐faulting regimes, the western margin of the Great basin and the eastern margin of the Sierra Nevada, forming a complex seismotectonic zone, and a possible nascent plate boundary

The 2020 M 6.5 Stanley, Idaho, earthquake produced rupture in the north of the active Sawtooth fault in the northern basin and range at depth, without any observable surface rupture. Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data yield several millimeters of static offsets out to ∼100 km from the rupture and up to ∼0.1 m of near‐field crustal deformation.

The 18 March 2020 Mw 5.7 Magna, Utah, earthquake was the largest earthquake in Utah since the 1992 ML 5.8 St. George earthquake. The geologic setting of the Magna earthquake is well documented by recent geologic mapping at 1:24,000 scale and 1:62,500 scale at and near the epicenter northeast of Magna, Utah. Subsurface fault modeling from surficial geologic mapping, structural cross sections, deep borehole

To better characterize seismic hazard, particularly, for induced seismicity, there is an increasing interest in methods to estimate moment magnitude (⁠Mw⁠) for small earthquakes. Mw is generally preferred over other magnitude types, but, it is difficult to estimate Mw for earthquakes with local magnitude (⁠ML⁠) <3–3.5⁠, using conventional moment tensor (MT) inversion. The 2020 Mww 5.7 Magna, Utah,

The 2020 Magna, Utah, earthquake produced observable crustal deformation over an ∼100 km2 area around the southeast margin of Great Salt Lake, but it did not produce any surface rupture. To obtain a detailed picture of the fault slip, we combine strong‐motion seismic waveforms with Global Positioning System static offsets and Interferometric Synthetic Aperture Radar observations to obtain kinematic