Iren ADELINA Moldovan

• PhD
• Head of Department at National Institutue of Research and Development for Earth’s Physics

Romania is known for its persistent seismicity at intermediate-depths in the Vrancea region. However, crustal areas are also a significant source of seismic hazard, although large shallow events are less common. This study is a first attempt to characterize statistically and propose a forecasting model for two recent aftershock sequences occurred a...

Carpathian Orogen represents a natural laboratory for studying geodynamic interactions between lithospheres of different ages. The ancient Archean Craton, such as the East European Craton, and Proterozoic platforms like the Scythian and Moesian platforms, collided with the younger Tisza and Dacia Mega-Units, resulting in the formation of the curren...

The NIEP (National Institute of Earth Physics) monitors and analyzes seismicity in Romania. Over time, the monitoring stations equipped with seismic equipment have become multifunctional with new devices for measuring gas emissions, the magnetic field, the telluric field, solar radiation, etc. This made it possible to introduce a seismic forecastin...

Romania is known for its persistent seismicity at intermediate-depths in the Vrancea region, however crustal areas are also a significant source of seismic hazard, although large shallow events are less common. This study is a first attempt to characterize statistically and propose a forecasting model for two recent aftershock sequences occurred at...

Romania is known for its persistent seismicity at intermediate-depths in the Vrancea region, however crustal areas are also a significant source of seismic hazard, although large shallow events are less common. This study is a first attempt to characterize statistically and propose a forecasting model for two recent aftershock sequences occurred at...

"In the absence of earthquakes, seismic stations continuously record the Earth's vibrations, called ambient seismic noise (ASN). The main concern regarding the ASN records is improving the seismic data quality using different tools developed especially for this purpose. Power Spectral Densities (PSD) and their corresponding Probability Density Func...

S12 -Recent Devastating Earthquakes Including the Feb. 6, 2023 Turkey SequenceVictorin- Poster: IUGG23-3282, S12p-088 TherecentsequenceofdevastatingearthquakesinTurkey(February6,2023)coincidedwiththeactivationoftheRâmnicuSăratseismiczoneinRomania.Afterthefirst7.8RearthquakeinCentralTurkey,2023-02-0601:17:36.1UTC,a4.6RearthquakefollowedshortlyinRoma...

Background: The intermediate-depth seismicity in the Vrancea region (Romania) is characterized by localized and persistent earthquake activity that culminates about two or three times in a century with the occurrence of a large event (M ≥ 6.5). Here we have revisited some important seismicity characteristics, using earthquake catalog data spanning...

The analysis of the relationship between radon and seismicity was previously carried out in the seismic zone of Vrancea (Romania), positioning the measuring stations on tectonic faults. This article analyzed the evolution of radon under conditions of deep and surface seismicity and the presence of mud volcanoes, as well as fires caused by gasses em...

Understanding the seismo–ionospheric coupling mechanism requires a quiet geomagnetic condition, as this represents an ideal situation to detect abnormal variations in the geomagnetic field. In reality, continuous interactions between solar wind and Earth’s magnetosphere create many fluctuations in the geomagnetic field that are more related to sun–...

The analysis of the radon-seismicity relationship has been carried out so far in the Vrancea (Ro-mania) seismic zone, with monitoring stations positioned on tectonic faults. The article analyzes the evolution of radon under the conditions of the existence of deep and surface seismicity and the presence of mud volcanoes along with live fires caused...

(1) Background: The intermediate-depth seismicity in the Vrancea region (Romania) is characterized by localized and persistent earthquake activity that culminates about two or three times in a century with the occurrence of a large event (M 6.5). Here we have revisited some important seismicity characteristics, using earthquake catalog data spannin...

The parameters influencing the sea level measured with ultrasonic devices that are analyzed in this paper are the air temperature, atmospheric pressure and wind speed. As these variations are independent to each other and to the sea level, they can be removed from the measured sea level by applying a filtering algorithm based on independent compone...

The Catalogue is a compilation containing 1299 events (Mw≥3.0) that occurred between 08.01.1223 and 31.12.1989 within the Intra-Carpathians Region of Romania. It can be accessed and downloaded at: Mendeley Data, doi: 10.17632/p8rgkfhjbz.2 The focal parameters of imported earthquakes have been revised using all primary data collected from the ava...

Seismic velocity is the geophysical property that has a key role in characterizing dynamic processes and the state of the stress around the faults, providing valuable information regarding the change in the tectonic regime. The stress in the crust is an important indicator of the possible occurrence of a major earthquake, and the variation of seism...

We designed a convolutional neural network application to detect seismic precursors in geomagnetic field records. Earthquakes are among the most destructive natural hazards on Earth, yet their short-term forecasting has not been achieved. Stress loading in dry rocks can generate electric currents that cause short-term changes to the geomagnetic fie...

Over the years, researchers have focused their attention on improving seismic data quality. Various tools have been developed for this purpose based on ambient seismic noise data. Seismic noise amplitude can be disturbed by numerous factors, increasing or decreasing due to human activity, traffic, wind speed, or other natural sources. In this study...

Many previous research studies have shown how local and even regional earthquakes can significantly affect the release of radon in the soil. The aim of this work is to investigate the relationship between radon measurements and the daily seismic activity rate and develop a methodology that allows estimating the seismic activity rate using only rado...

This database was published in two papers: 1. E. OROS, M. POPA, I. A. MOLDOVAN (2008). SEISMOLOGICAL DATABASE FOR BANAT SEISMIC REGION (ROMANIA) - PART 1: THE PARAMETRIC EARTHQUAKE CATALOG. Romanian Journal of Physics 53 (7-8): 955-964 2. E. OROS, M. POPA, E. POPESCU, I. A. MOLDOVAN (2008). SEISMOLOGICAL DATABASE FOR BANAT SEISMIC REGION (ROMANIA)...

In the absence of earthquakes, seismic stations continuously record the Earth's vibrations, called ambient seismic noise (ASN). The main concern regarding the ASN records is improving the seismic data quality using different tools developed especially for this purpose. Power Spectral Densities (PSD) and their corresponding Probability Density Funct...

The goal of this paper is to develop a new empirical relationship between observed macroseismic intensity and strong ground motion parameters such as peak ground acceleration (PGA) and velocity (PGV) for the Vrancea subcrustal earthquakes. The recent subcrustal earthquakes provide valuable data to examine these relationships for Vrancea seismogenic...

The main target of this paper is to established a correlation between the seismicity of the Western part of Southern Carpathians (Romania) and the active tectonic (faults systems) of the area, the second target is to create a specific database of the faults (ROmanian DAtabase of SEismogenic Faults-RODASEF) in SHARE manner, for seismic hazard assess...

The purpose of this study consists in the analyses of ETAS (Epidemic-Type Aftershock Sequence) parameters for the sequence recorded on November 22 nd , 2014 in Marasesti area. The main shock of the sequence, a moderate-size earthquake with M L = 5.7, at 40.9 km depth, is the largest crustal event instrumentally recorded at the bending of the Easter...

Large-scale radon monitoring is carried out due to the fact that it is directly responsible for public health. European Directive 2013/59/EURATOM has been transposed into the legislation of several countries and provides for the need for long-term monitoring of radon in homes and workplaces by setting the average annual reference level at 300 Bq/m³...

Modelling the causal relationship between the stress field specific to a complex geological environment as structure and composition and how it reacts and manifests itself through specific, observable and measurable deformations (fracturing and propagation of fractures, seismic faults, seismicity), is the key to understanding seismogenic processes...

The paper presents a seismotectonic model of the Southern Carpathians obtained from the analysis of the seismicity-stress field-geology and tectonics relationship. The seismicity model is based on a revised earthquake catalogue. The distribution of b-values in the 3D space facilitated the identification of stressed areas and asperities with reactiv...

This paper discusses the use of ground magnetometer data to seismogenic zones and presents the relationship between anomalous geomagnetic variations and the occurrence of the intermediate-depth earthquakes. The present paper highlights the geomagnetic anomalies recorded at Muntele Rosu Seismological Observatory (MLR), between 2008 and 2013. To dist...

We present the study of the earthquakes sequence from 25 June to 6 July 2020 occurred in the western South Carpathians. The main shock had Io= VMSK, Mw= 4.1, occurred at h= 16 km, was preceded by a foreshock (Mw= 3.2) and has 16 after-shocks (Mw= 1.6–4.1) concentrated in the depth range 14–21 km. The focal mechanisms are characterized by strike-sli...

This study analyzes the possibility to use geophysical and geochemical parameters in an OEF (Operational Earthquake Forecasting) application correlated with short-term changes in seismicity rates using a magnitude–frequency relationship. Tectonic stress over the limits of rock elasticity generates earthquakes, but it is possible that the emission o...

The aim of the present paper is to test intensity attenuation relationships for subcrustal earthquakes occurred in Vrancea (Romania) seismogenic zone in relation with some important dams situated in extra-Carpathian area. During centuries, the Romanian territory has been shaken by strong earthquakes, most of them being centered within Vrancea Zone,...

The seismic hazard studies of the last 30 years have been largely carried out taking into account the needs of the construction engineers, by linking the specific quantities of soil movement with the physical parameters determined instrumentally, namely, with the maximum values of soil acceleration. At present, interest in the results of hazard stu...

In this paper, we have studied the seismic activity in relation with geology, and tectonics in order to highlight seismogenic processes recorded in Danubian area and Hateg-Strei Basin. The Danubian seismogene area presents a complex geological structure, being characterized by the following tectonic units: Median Dacides (Getic and Supra-Getic napp...

Romania is one of the most seismic-prone countries in Europe due to the periodically occurrence of strong intermediate-depth earthquakes in Vrancea seismogenic zone. The Vrancea area is located beneath the South-Eastern Carpathian Arc bend, at the contact between the East - European plate and the Intra-Alpine and Moesian sub-plates. An intense seis...

The solar radiation affects the life on Earth and it is important in meteorology, climatology, solar energy, agriculture, hydrology and seismology, too. The Sun warms the earth which reflects a part of the energy. An effect of tectonic stress increases the ground temperature that is radiated into the atmosphere. We study the possibility to use the...

A correct seismic hazard assessment and intensity-based shake maps of a seismic zone depend on the determination of parameters that emphasize the distribution and the macroseismic intensity attenuation for that seismogenic zone. Due to the reduced number of strong ground motion records, macroseismic intensity information available for previous eart...

1. Abstract Gas emission is a precursor factor in a seismic area. This presentation refers to the monitoring of radon and CO 2 in Vrancea, the area characterized by deep earthquakes at the curvature of the Carpathian mountains. The methods are general but are customized to the geological specificity of the area under investigation. Fault areas have...

In the present paper, a relationship between geomagnetic anomalies recorded at one magnetometer located inside Vrancea seismogenic zone and the occurrence of intermediate earthquakes is examined. To better distinguish the regional anomalies from global geomagnetic storms, the datasets were correlated with the geomagnetic indices taken from NOAA/Spa...

The main target of this paper is to established a correlation between the seismicity of the Eastern part of Romania and the active tectonic (faults systems) of the area, the second target is to create a specific database of the faults (ROmanian DAtabase of SEismogenic Faults-RODASEF) in SHARE manner, for seismic hazard assessment process. This pape...

We use short-term earthquakes forecast for help organizations specialized in emergencies situation in Romania (Inspectorate for Emergency Situation network). Our case study refers of seismic evolution in Vrancea area (the curving area of the Carpathian Mountains) and analysis the reliability to estimate the seismicity in this active zone characteri...

Abstract. In this study were used geomagnetic data recorded during last 5 years, from 2013 till present. The records were corrected for missing and wrong data induced by malfunction of the data acquisition system. The main purpose of the paper is to identify the magnetic field behaviour in relation with space weather, meteorological phenomenon incl...

VLF/LF (20-300 kHz) radio waves propagation is affected by different factors such as meteorological conditions, solar bursts and geomagnetic activity. At the same time, variations of some parameters in the ground, in the atmosphere and in the ionosphere occurring during the preparatory phase of earthquakes can produce disturbances in the propagatio...

The goal of this paper is to present a comparative study of the people perception from two different sites from Romania and France, regarding the tsunami risk in the Black and Mediterranean Seas communities. These two surveys over residents’ and tourists’ perception and preparedness of tsunami hazard were carried out for both towns, Eforie Nord(Rom...

There are evidences of 22 past tsunamis generated in the Black Sea area. Shabla area is the most dangerous for the Romanian shoreline and triggered past high magnitude earthquakes and tsunamis. According to National Oceanic and Atmospheric Administration (NOAA) data base, 3 important events occurred in Shabla: the most recent, on 31st of March 1901...

The paper presents a detailed analysis of the seismic activity recorded in the Banloc-Voiteg seismogenic structure (Romania) located on the southeastern border of the Pannonian Depression which is characterized by pre-Alpine and Alpine structures belonging to Tisa-Dacia Microplate and, particularly by the tectonic contact between two main geodynami...

Seismic active zones have particularities generated by geological structure. For this reason seismic precursors and analysis methods differ. Tectonic stress is permanent and generates increasing effects when an earthquake occurs. Prediction is impossible but sometimes short-term forecast is possible. We created a multidisciplinary network (AeroSolS...

The goal of this paper is to present some observations about the abnormal animal behavior prior to and during some Romanian subcrustal earthquakes. The major Vrancea earthquakes of 4 March 1977 (MW = 7.4, Imax = IX–X MSK), 30 August 1986 (MW = 7.1, I0 = VIII–IX MSK) and 30 May 1990 (MW = 6.9, I0 = VIII MSK), were preceded by extensive occurrences o...

In the last decade, many efforts were done to predict the macroseismic intensity in case of felt Vrancea earthquakes and additionally an online environment was developed for the automatic approximation of the intensity from peoples’ feedback. Besides the extended scientific studies, the near real-time estimation of the macroseismic intensity recent...

The Vrancea seismic region, located at the bending area of the South–Eastern Carpathians in Romania, is the most active zone of seismicity in Europe, producing earthquakes at intermediate depths (60–200 km). The major events (magnitude above 7) are generated at intermediate depth and produce specific patterns of damage over extended areas. In this...

Previous studies have shown that the Black Sea was subject to tsunami waves generation in the past (Altinok, 1999), with a total of twenty-two events generated. According to recent studies of Diaconescu et al. (2008), the Black Sea is divided in nine seismic sources. A more recent approach structures the area in ten different seismic sources, given...

The paper has as final goal the probabilistic assessment of seismic hazard in the Black Sea area as input for the tsunami hazard evaluation. Maximum and most expected magnitudes and their recurrence periods have been computed for all defined seismogenic sources from the marine area, and hazard curves have been plotted.

Our multidisciplinary network (AeroSolSys) located in Vrancea (Curvature Carpathian Mountains) includes radon concentration monitoring in five stations. We focus on lithosphere and near surface low atmosphere phenomena using real-time information about seismicity, + /-ions, clouds, solar radiation, temperature (air, ground), humidity, atmospheric p...

Ionospheric TEC (Total Electron Content) variations and Low Frequency (LF) signal amplitude data prior to three large earthquakes (M≥6) in Greece were analyzed using observations from the Global Navigation Satellite System (GNSS) and the European INFREP (International Network for Frontier Research on Earthquake Precursors) networks respectively, ai...

On November 22, 2014, at 21:14:17 local time (19:14:17 GMT) an earthquake of local magnitude ML=5.7 occurred in the proximity of Marasesti city in Vrancea county (Romania) in the lower crust (39 km depth). It was the largest event recorded since 120 years in this area (the maximum magnitude was estimated at Mw 5.9 for an event occurred on March 1,...

In this study we have used the most reliable and homogeneous seismic datasets at the European scale, covering historical and modern instrumental seismicity until present days for the Eastern part of Romania and the Black Sea Area for computing the statistical parameters of seimogenic sources and assessing the probabilistic hazard in the South Easte...

1. Abstract Our multidisciplinary network (AeroSolSys) located in Vrancea (Curvature Carpathian Mountains) includes radon concentration monitoring in five stations. We focus on lithosphere and near surface low atmosphere phenomena using real-time information about seismicity, + /-ions, clouds, solar radiation, temperature (air, ground), humidity, a...

Between years 2001 and 2004 a number of earthquakes with magnitudes which ranged from 3.9 to 5.0 occurred in the most seismically active areas of the Romanian territory. A macroseismic analysis of the effects produced on the Romanian territory has been conducted for these earthquakes, by using macroseismic questionnaires. Some of the observed inten...

This paper describes the modalities of detection of events in a multidisciplinary network that monitor seismicity, telluric field, magnetic field, electric-electrostatic field, radio ULF waves, air ionization, radon concentration, solar radiation, infrasound, light and acoustic phenomena, meteorological parameters, air-earth temperatures, satellite...

We examine the lithosphere-atmosphere-ionosphere interaction with respect to earthquake events using Total Electron Content (TEC) data deriving from the Romanian permanent GPS network by applying three different techniques: a) estimation of TEC deviations from the mean state, b) Cross-Correlation Analysis and c) Spectral Analysis. The analysis conc...

The Romanian VLF / LF monitoring system consists in a radio receiver and the infrastructure that is necessary to record and transmit the collected data, and is part of the international initiative INFREP and was put into operation in December 2009 on the Black-Sea shore (Dobruja Seismologic Observatory - Dob-RO). Since then the system was developed...

The paper describes a complex multidisciplinary monitoring system designed for Vrancea seismic area (bending area of Carpathians Mountains). This includes hardware (stations with sensors, acquisition and communication equipment) and software for data processing in real time. The result of this work is the growth of an alert service through: perfect...

In the last decades, one of the main research directions in identifying seismic precursors involved monitoring VLF (Very Low Frequency) and LF (Low Frequency) radio waves and analysing their propagation characteristics. Essentially this method consists of monitoring different available VLF and LF transmitters from long distance reception points. Th...

Vrancea's seismicity (Curvature Carpathian mountains) recorded in 2013 an energy discontinuity preceded by the highest seismic inactivity according to the Romanian National Institute for Earth Physics. The energy is calculated based on the local magnitude (Richter), and is cumulative. Vrancea is the most important seismic region from Eastern Europe...

The main goal of this paper is rating the dams from the Western part of Romania into seismic risk classes. Dam owners and regulators must ensure that dams are safely operated and present no risk to the public in case of an earthquake. While most dams close to Vrancea seismic region have been evaluated and analyzed for seismic loads, dams located in...

The Black Sea area is liable to tsunamis generation and the statistics show that more than twenty tsunamis have been observed in the past. The last tsunami was observed on 31st of March 1901 in the western part of the Black Sea, in the Shabla area. An earthquake of magnitude generated at a depth of 15 km below the sea level , triggered tsunami wave...

Since 2009 a network of VLF (20-60 kHz) and LF (150-300 kHz) radio receivers has been put into operation in Europe in order to study earthquakes precursors. At the moment the network consists of ten receivers three of which are located in Italy, two in Greece and one in Portugal, Romania, Malta, Cyprus and Turkey. The data (sampling rate of 1min) a...

Large and destructive intermediate-depth earthquakes in Vrancea, Romania,have been generated about every century in the last millenium. Possible precursors, such as bio-location reactions obtained across crustal faults, or three component geomagnetic continuous recordings, have been used in the last decade in and around the Vrancea region. After-th...

The paper brings together, in the same frame, the solar activity, the seismicity and the geomagnetic field behavior. Using statistical approaches, we try to find a degree of correlation between the three phenomena. On one part, the solar activity influences the geomagnetic field, giving rise to two types of variations: regular and irregular variati...

The National Institute for Earth Physics (Romania) operates one of the largest seismic networks in the Eastern Europe. The network includes 97 stations with velocity sensors of which 52 are broadband and 45 are short period, 102 strong motion stations and 8 seismic observatories. Located in the most active seismic region of Romania, i.e. Vrancea ar...

In 2009, INFREP, a network of VLF (20-60 kHz) and LF (150-300 kHz) radio receivers, was put into operation in Europe having as principal goal, the study of disturbances produced by the earthquakes on the propagation properties of these signals. On May 22nd, 2012 an earthquake with Mw=567 occurred in Bulgaria, near Sofia, inside the "sensitive" area...

In this study we will use both Cornell and extreme values (Gumbel I) distributions to model the seismogenic process for all the earthquake sources located around and across the Black Sea region and to compute all the quantities used in probabilistic hazard assessment. The differences in methods have effects in results distribution and the challenge...

Large and destructive intermediate-depth earthquakes in Vrancea have been generated about every century during the last millennium. Possible earthquake precursors, such as bio-location data obtained across crustal faults, and three component magnetic continuous recordings, have been used in the last decade in and around the Vrancea region. After-th...

The Vrancea seismically active region of Romania, situated far-from active plate boundaries, can be characterized by small-large intermediate-depth earthquakes and small-moderate normal ones. The intermediate-depth earthquakes are destructive when larger than magnitude Mw 7.2. A bio-location methodology has been used trying to map crustal faults in...

Since 2009 a network of VLF (20-60 kHz) and LF (150-300 kHz) radio receivers is operating in Europe in order to study the disturbances produced by the earthquakes on the propagation of these signals. In 2011 the network was formed by nine receivers, of which three are located in Italy and one is in Austria, Greece, Portugal, Romania, Russia and Tur...

p>In 2008, a radio receiver that works in very low frequency (VLF; 20-60 kHz) and LF (150-300 kHz) bands was developed by an Italian factory. The receiver can monitor 10 frequencies distributed in these bands, with the measurement for each of them of the electric field intensity. Since 2009, to date, six of these radio receivers have been installed...

Since 2009 a network of VLF (20-60 kHz) and LF (150-300 kHz) radio receivers was put into operation in Europe in order to study the disturbances produced by the earthquakes on the propagation of these signals. In 2011 the network was formed by nine receivers located three in Italy and one in Austria, Greece, Portugal, Romania, Russia and Turkey. On...

Since 2009 a network of VLF (20-60 kHz) and LF (150-300 kHz) radio receivers was put into operation in Europe in order to study the disturbances produced by the earthquakes on the propagation of these signals. In 2011 the network for LF signals was formed by six receivers located two in Italy and one in Greece, Portugal, Romania, and Turkey. The L...

We report on low frequency (LF) transmitter signal recorded by the 'Instrument Capteur Electrique' (ICE) experiment onboard the DEMETER micro-satellite. We mainly consider the signal emitted by the Brasov broadcasting station (25.60E, 45.75N) at frequency of about 153 kHz. We analyze the reception conditions of this transmitter several weeks before...

Geomagnetic variations associated with earthquakes are widely accepted and several anomalous geomagnetic observations have been interpreted as a result of changing rock magnetic properties under varying tectonic stress (piezomagnetic effect). During the last 15 years of geomagnetic investigations conducted in Vrancea seismogenic zone, period coveri...

The Romanian VLF/LF monitoring system consisting in a radio receiver and the infrastructure that is necessary to record and transmit the collected data is part of the European international network named INFREP. Information on electromagnetic fields' intensities created by transmitters at a receiving site are indicating the quality of the propagati...

Study events belong to three seismogenic zones in the South Carpathians area: Ramnicu Sarat - 2 sequences on November 29, 2007 (main shock, 45.62oN, 27.22oE, h=19 km, M = 3.9) and December 6, 2009 (main shock, 45.39oN, 26.98oE, h=25 km, M = 4.2); Vrincioaia - one sequence on September 6, 2008 in (main shock, 45.80oN, 26.51oE, h=13 km, M = 4.4); Fag...