Alexandru Marmureanu

National Institute for Earth Physics · National Seismic Network

This study presents recent advances in developing a joint decision-support system for Romania which connects the Romanian Earthquake Early Warning System, recordings of seismic sensors in free-field and in buildings, data-driven Structural Health Monitoring, ShakeMaps and rapid loss estimation methodologies. The goal of this system is to provide in...

With the growing exposure of urban areas in seismic countries as Romania, in terms of buildings and population, it is of paramount importance to characterize at best both the built environment and the near surface. At urban and building scale level, the MULTICARE project will improve the existing methodologies and deliver technical and scientific k...

The recent crustal earthquake sequence in Gorj Area, Romania, consisted of a doublet, as main shocks, followed by more than 3400 aftershocks, according to the preliminary earthquake catalogue. The main shocks were a 4.8 MW earthquake on February 13, 2023, followed by a 5.4 MW earthquake on February 14. The strongest aftershock was a 4.6 MW earthqua...

An intense seismic activity started in February 2023, close to Targu Jiu city, in the Oltenia region (Romania). The strongest events occurred on 13th and 14th February, the first shock with ML=5.2, and respectively the second shock with ML=5.7. These main shocks were followed by specific seismicity bursts (about 2000 foreshocks were registered). Th...

An intense seismic activity started on February, 2023, close to Targu Jiu city, in Gorj region (Romania), as part of the Getic Depression. The earthquakes were located nearby the contact between Getic Depression and the Carpathians orogen. The seismic sequence consisted of more than 3100 foreshocks with the highest magnitude of Mw=4.9 (occurred on...

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...

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...

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...

This preliminary report presents the main ground motion parameters (GMP) for engineering applications: Acceleration, Velocity, Displacement, PGA, PGV, PGD, SA, SV, SD and Fourier Spectra.

The seismicity of Romania is mostly represented by earthquakes produced by the Vrancea seismic source with intermediate depth events (3 shocks/century with magnitude MW greater than 7.0). The seismic activity in Romania also includes crustal earthquakes. The crustal seismicity is more scattered and moderate compared to the intermediate-depth one. A...

The Vrancea slab, Romania, is a subducted remnant of the Tethyan lithosphere characterized by a significant intermediate-depth seismicity (60–170 km). A recent study showed a correlation between this seismicity and major dehydration reactions, involving serpentine minerals up to 130 km depth, and high-pressure hydrated talc deeper. Here we investig...

The Vrancea seismic zone, located in the bend region of the South-Eastern Carpathians, is a unique area with both crustal and intermediate-depth seismic activity and is known as one of the most active seismic area in Europe. Moderate crustal seismicity is recorded all over the Carpathian region, but the far more intense activity occurs in a small s...

Earthquakes are one of the most challenging natural hazards to manage by emergency situation authorities: they are unpredictable, can cause widespread losses in a matter of seconds and can trigger additional hazards (tsunamis, landslides, explosions etc.). Quick reliable information is vital for an effective rapid response, considering that life ex...

The Earthquake Early Warning (EEW) and Structural Health Monitoring (SHM) systems can significantly contribute to seismic risk mitigation in regions with high seismic hazard. Romania, a country periodically affected by strong earthquakes with magnitude > 7.0 occurring in the the Vrancea intermediate-depth seismic zone benefits from both systems. Fo...

The Near Fault Observatories (NFOs) community is one of the European Plate Observing System (EPOS, http://www.epos-eu.org) Thematic Communities, today consisting of six research infrastructures that operate in regions characterised by high seismic hazard originating from different tectonic regimes. Earthquakes respond to complex natural systems who...

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...

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 sta...

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 Seis...

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) coordina...

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

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...

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...

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...

A multidisciplinary network is monitoring a seismic area from Romania, Vrancea, sitting at curvature of Carpathian Mountains. The last major earthquake here produced distant effects (Moscow, Istanbul) in 1977 with Mw = 7.4 and there is a high probability of having a similar event soon. Romania has a large seismic network and 10 multidisciplinary st...

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...

Near Fault Observatories (NFOs) are innovative research infrastructures based on dense, state of the art networks of multi-parametric sensors that continuously monitor the underlying Earth instability processes over a broad time interval. They aim at understanding the physical/chemical processes responsible for earthquakes and faulting and tracking...

Bucharest, with a population of approximately 2 million people, has suffered damage from earthquakes in the Vrancea seismic zone, which is located about 170 km from Bucharest, at a depth of 80–200 km. Consequently, an earthquake early warning system (Bucharest Rapid earthquake Early Warning System or BREWS) was constructed to provide some warning a...

Natural disasters from earthquakes can cause considerable damages, with potentially severe effects to urban environment. Last strong Vrancea earthquake on March 4, 1977 (Mw=7.4, depth=95km); tens of thousands of buildings damaged, many people injured and dead. Strong earthquakes in the Vrancea zone occur between 60-200 km depth within an almost ver...

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...

European researchers and seismic networks are active in developing new approaches to earthquake early warning (EEW), implementing and operating test EEW systems, and in some cases, offering operational EEW to end users. We present the key recent developments in EEW research in Europe, describe the networks and regions where EEW is currently in test...

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...

Vrancea earthquake on November 10th, 1940 (MW = 7.7; MGR = 7.5; h = 150 km; E = 1.122 × 1023 ergs, Imax = IX½) represents the first large earthquake in the last century and was preceded by other earthquakes as: October 22, 1940 (MW = 6.5) and November 8, 1940 (MW = 5.9). If recorded, it would be given the opportunity to get basic data for seismic h...

An unusual seismic swarm started on September 23, 2013, close to Galati city, in Izvoarele region (Romania), and lasted until November 12, 2013. 406 earthquakes were recorded during several phases of seismic activity. The strongest events—a magnitude 3.9 earthquake, occurred on September 29, and two ML 3.8 shocks, occurred on October 3 and 4, respe...

The goal of this study is to analyze the seismic activity of the Vrancea intermediate depth source zone during the period 2010-2015, time interval when the data provided by the National Seismic Network reached high quantitative and qualitative levels. The Vrancea undercrustal source (60-200 km depth) is located in a small focal volume at the Carpat...

Seismic hazard is quantified by three parameters: level of severity, and spatial and temporal measurements. Thus, the purpose of a seismic hazard assessment is to determine these three parameters from instrumental, historical and geological observations. The characterization of earthquake ground motion for engineering applications generally involve...

The seismic activity on the Romanian territory consists of both crustal and intermediate-depth earthquakes. The crustal seismicity is moderate and more scattered compared to the intermediate-depth one. In this paper we study the problem of homogeneous determination of local magnitude for earthquakes from the main seismic zones of Romania (Vrancea,...

In Romania, there is an operational early warning system that is able to send earthquake location and magnitude since 2013. Romanian territory, together with the neighbor countries Moldova, Ukraine and Bulgaria, are periodically affected by the intermediate depth earthquakes originating from Vrancea area. In order to rapidly locate and estimate mag...

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...

Although a rare phenomenon, tsunamis in the Black Sea were generated in the past, studies showing more than twenty events observed (Altinok Y., 1999). Earthquakes monitoring in the Black Sea as well as a database with tsunami modeling Scenarios could lead to a better understanding of such phenomena. A set of 6 past earthquakes were taken into consi...

In this paper we present the results obtained during the study of swarm of earthquake close to the Galati city. In the last period the National Seismic Network was continuously upgraded, which allows presently to easily detect earthquakes with very low magnitudes in every seismic region of Romania. The seismogenic region of the swarm is situated be...

The systematic studies of the focal mechanism solutions furnish fundamental data about some of the main factors that control the seismic phenomenon, e.g. stress field peculiarities and the types of faulting, the geometry of the faults and provide critical information for global, regional and local tectonic studies, as well as for many types of seis...

In seismic hazard evaluation and risk mitigation, there are many random and epistemic uncertainties. On the another hand, the researches in this area as part of knowledge are with rest, that is, the results are with interpretable questions with open answers. The knowledge cannot be exhausted by results. The authors developed in last time the concep...

The response of any physical system is nonlinear unless the magnitude of the input is very small. The MW magnitudes of deep Vrancea earthquakes are between 0.02 and 7.9. The leading question is: how many cities, villages, metropolitan areas etc. in seismic regions are constructed on rock sites? Most of them are located on alluvial deposits, on Quat...

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...

Providing warning notification several seconds before dangerous earthquake waves arrive at a target site reduces the property damages and human casualties. Most earthquake early warning systems (EEWS) developed are either regional (“network based”) or on-site (“stand alone”) systems. The recent upgrade of the seismic network in Romania with high dy...

The study is dedicated to Rapid Seismic Alarm System (RSAS) alarm time assessment, for Republic of Moldova (RM) territory (case study - Chisinau city).The seismic wave propagation aspect is reduced to a statistical study of recorded data, provided by ISC bulletin (1965-2012) for Vrancea seismogenic area, and use of regional structure models (HYPO+)...

The program analyzes seismicity on a defined area with the use of bulletins (event information) provided by ANTELOPE software. These include earthquake localization (moment, latitude, longitude, magnitude, depth, P and S for each station and other parameters). The evolution of the calculated energy from the Richter magnitude is characterized by ste...

Geomagnetic research involves a continuous Earth's magnetic field monitoring and software for processing large amounts of data. The Analysis_IAGA program reads and analyses files in IAGA2002 format used within the INTERMAGNET observer network. The data is made available by INTERMAGNET (http://www.intermagnet.org/Data_e.php) and NOAA - National Geop...

The response of any physical system is nonlinear unless the magnitude of the input is very small. The M-w magnitudes of deep Vrancea earthquakes are between 0.02 and 7.9. The leading question is: how many cities, villages, metropolitan areas etc. in seismic regions are constructed on rock sites? Most of them are located on alluvial deposits, on Qua...

Earthquake represents a major natural disaster. The main problem after the occurrence of a strong earthquake is to minimize the total number of fatalities. As a consequence, a rapid early warning system was developed in Romania that provides a 25-32 seconds warning time to Bucharest facilities for Vrancea earthquakes. The Rapid Earthquake Warning S...

In a world of uncertainty, the only constant is change and rapid change produces a multitude of diverse facts. Risk is an integral part of life. While no country in the world is entirely safe, the lack of capacity to limit the impact of hazards remains a major burden for all countries and while the world has witnessed an exponential increase in hum...

The central point of the discussion in last 10-15 years was whether soil amplification is function of earthquake magnitude. Laboratory tests made by using Hardin or Drnevich resonant columns consistently show the decreasing of dynamic torsion function (G) and increasing of torsion damping function (D%) with shear strains (γ) induced by deep strong...

The need to use early warning methods to reduce natural risks in modern societies is related to their unprecedented dependence upon technology. The strong deep events originating from Vrancea-Romania (Mw =7.5) area and shallow events originating from Banat-Romania or Shabla-Bulgaria areas can generate destructive effects in Romania and neighbor co...

The Vrancea seismogenic zone in Romania represents a peculiar source of seismic hazard, which is a major concern in Europe, especially to neighboring regions of Bulgaria, Serbia and Republic of Moldavia. Earthquakes in the Carpathian–Pannonian region are confined to the crust, except the Vrancea zone, where earthquakes with focal depth down to 200...

Nonlinear effects in ground motion during large earthquakes have long been a controversial issue between seismologists and geotechnical engineers. Laboratory tests made by using resonant columns consistently show the reduction in shear modulus (G) and increase in damping ratio (D) with increasing shear strain (γ), i.e., G = G(γ), respectively, D =...

The last zonation seismic map has areas where seismic intensities are under evaluated (e.g. Dobrogea, Banat etc.), and other areas are over-evaluated. The fundamental unacceptable point of view is that this design code is in peak ground accelerations which generates a lot of drawbacks to civil structural designers and to insurance companies which a...

The Romanian territory is exposed to high seismic risk associated to earthquakes occurring in Vrancea area. Major earthquakes occurred in this area in the last century: November 10, 1940, (Mw=7.7; h=140 km); March 4, 1977(Mw=7.4; h= 95 km); August 30, 1986(Mw=7.1; h=130 km) and May 30, 1990(Mw=6.9;h=90 km). The deep earthquakes (MW =7.9) generated...

Nonlinear effects in ground motion during large earthquakes have long been a controversial issue between seismologists and geotechnical engineers. Aki wrote in 1993:"Nonlinear amplification at sediments sites appears to be more pervasive than seismologists used to think...Any attempt at seismic zonation must take into account the local site conditi...

The last zonation seismic map, existing since 1993, has areas where seismic intensities are sub-evaluated (Dobrogea, Banat etc.), and other areas are over-evaluated. Intensities I=IX on MMI scale, at which corresponds a 0.4 g level of acceleration, and 0.8 g at rupture/yielding, make Vrancea county to become an unsustainable development area for th...

The deep earthquakes generated in Vrancea area are particularly of interest for many countries in Europe since they cause destructive effects at large distances from Moscow to Roma. Main courses for specific actions to mitigate the seismic risks given by strong deep Vrancea earthquakes should be considered as key for development actions and one of...

The seismic hazard of Romania has been the object of several studies based on probabilistic or deterministic methods (1). Details of the resulted hazard maps are still a controversial issue that leads to an innovative approach: a combined analysis of the available records and macroseismic information completed with numerical simulations since the s...

Due to the huge amount of recorded data, an automatic procedure was developed and used to test different methods to rapidly evaluate earthquake magnitude from the first seconds of the P wave. In order to test all the algorithms involved in detection and rapid earthquake magnitude estimation, several tests were performed, in order to avoid false ala...

The seismicity of Romania comes from the energy that is released by crustal earthquakes, which have a depth not more than 40 km, and by the intermediate earthquakes coming from Vrancea region (unique case in Europe) with a depth between 60 and 200 km. The authors developed the concept of "control earthquake"and equations to obtain the banana shape...

A prototype early warning system was developed in Romania in order to provide 25-35 seconds warning time for Bucharest facilities for earthquake with M >6.5. The prototype system consists of four components: network ground motion sensors in the epicentral area, an area centre in epicentre, a digital radio communication link and a central data centr...

EWS made by NIEP is the first European system for real-time early detection and warning of the seismic waves in case of strong deep earthquakes. EWS uses the time interval (28-32 seconds) between the moment when earthquake is detected by the borehole and surface local accelerometers network installed in the epicenter area (Vrancea) and the arrival...

Nowadays natural disasters phenomena as hurricanes, volcanic eruptions, tsunamis or earthquakes, are still difficult to prevent. Based on signaling of the phenomenon appearance in the destructive area, important human losses and material damages are avoided. For that reason, WARNING turns into a key objective, both in theoretical and practical rese...