Alexandru Marmureanu

An Early Warning System for Deep Vrancea (Romania) Earthquakes

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 research.

State-of-the art and future of earthquake early warning in the European region

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 testing or development, and highlight the two systems in Turkey and Romania that currently provide operational systems to a limited set of end users.

Analysis of the Seismic Activity in the Vrancea Intermediate-Depth Source Region During the Period 2010–2015

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 Carpathian Bend, and it dominates the seismicity of Romania. The data set consists of 1603 earthquakes with local magnitudes 1.8 ≤ ML ≤ 5.5, recorded between January 2010 and October 2015. The events were localized using ANTELOPE software for data acquisition and processing. The reliable P-wave polarities were used to estimate the focal mechanism of 80 earthquakes with ML ≥ 3.8.

Rapid Earthquake Early Warning (REWS) in Romania: Application in Real Time for Governmental Authority and Critical Infrastructures

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 magnitude are used a few seconds of strong motion acceleration data. The alert notification broadcasting to users uses an internal communication network built on redundant links with a very high availability. When an earthquake is detected at the surface by the 24 bits accelerometers and velocity sensors, the digital seismic data is sent in real time to the National Institute for Earth Physics where the first 4 s of data are analyzed and alert is issued. The alert is sent to the users using TCP/IP or UDP communication protocols. At the emergency response units there are computers and dedicated devices that have three levels of warning according to the magnitude of the earthquake. Warning levels are associated to different management systems of strategic facilities than can block or enable automatically chosen activities of those facilities. The REWS is sending alerts also to civil protection and Koslodui power plant, in the northern part of Bulgaria. Since the REWS is able to rapidly locate events and compute magnitude, there were no false alerts recorded and were issued 19 earthquake alerts for earthquakes with M > 4.0.

Bridging the Gap Between Nonlinear Seismology as Reality and Earthquake Engineering

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 concept of “Nonlinear Seismology – The Seismology of the XXI Century” (Marmureanu et al. Nonlinear seismology-the seismology of XXI century. In: Modern seismology perspectives, vol 105. Springer, New York, pp 49–70, 2005).