Regional seismic hazard for Revithoussa, Greece: an earthquake early warning Shield and selection of alert signals

Abstract

Abstract. The feasibility of an earthquake early warning Shield in Greece is being explored as a European demonstration project. This will be the first early warning system in Europe. The island of Revithoussa is a liquid natural gas storage facility near Athens from which a pipeline runs to a gas distribution centre in Athens. The Shield is being centred on these facilities. The purpose here is to analyze seismicity and seismic hazard in relation to the Shield centre and the remote sensor sites in the Shield network, eventually to help characterize the hazard levels, seismic signals and ground vibration levels that might be observed or create an alert situation at a station. Thus this paper mainly gives estimation of local seismic hazard in the regional working area of Revithoussa by studying extreme peak ground acceleration (PGA) and magnitudes.Within the Shield region, the most important zone to be detected is WNW from the Shield centre and is at a relatively short distance (50 km or less), the Gulf of Corinth (active normal faults) region. This is the critical zone for early warning of strong ground shaking. A second key region of seismicity is at an intermediate distance (100 km or more) from the centre, the Hellenic seismic zone south or southeast from Peloponnisos. A third region to be detected would be the northeastern region from the centre and is at a relatively long distance (about 150 km), Lemnos Island and neighboring region. Several parameters are estimated to characterize the seismicity and hazard. These include: the 50-year PGA with 90% probability of not being exceeded (pnbe) using Theodulidis & Papazachos strong motion attenuation for Greece, PGA NTP ; the 50-year magnitude and also at the 90% pnbe, M 50 and M P50 , respectively. There are also estimates of the earthquake that is most likely to be felt at a damaging intensity level, these are the most perceptible earthquakes at intensities VI, VII and VIII with magnitudes M VI , M VII and M VIII . Example results (from many) include the corresponding parameters describing the hazard for Revithoussa as follows: PGA NTP : 203 cm s −2 , M 50 : 6.5, M p50 : 6.9, M VI : 5.8, Correspondence to: Y. Xu (y.b.xu@uea.ac.uk) M VII : 6.1 and M VIII : 6.4. These data are also useful in selecting expected alert-signals i.e. examples of strong ground vibration histories that might be expected at a Shield station in the alert situation.

Next-Generation EEW Empowered by NDSHA: From Concept to Implementation

“…The detailed description of the exploitation of the MMI database is shown in Figure 8 and its caption. (6) The magnitude is reset to 5.0 (and the depth to 10 km), the source is moved to t 2nd source cell (99.8°~100.0° E, 32.0°~32.2°N), and steps ( 2)-( 4) are repeated. Finally, after finishing the computations above, one will obtain 3264 results, i.e., 32 MMI maps for 3264 earthquake scenarios.…”

“…In the history of seismology [3], EEW played an essential role in protecting lifelines and economy in the world. In today's world, the implementations of EEW can be grossly divided into three types: (1) in operation, e.g., Romania [4], Turkey [5], Greece [6], America [7], Mexico [8], Chile [9], Japan [10][11][12]; (2) in progress, e.g., Italy [13][14][15], China (https://www.globaltimes.cn/content/1203521.shtml, accessed on 10 August 2021); (3) in planning, e.g., Iran [16,17] and Kyrgyzstan [18].…”

Himalayan Tectonic Belt: Morlet Wavelet Variation and Seismic Harmony

“…Elsewhere we have attempted to describe temporal and spatial patterns and fabrics of seismicity by adopting Cox, fractal and Hurst models of the seismic process (e.g. Xu, 1992;Xu & Burton, 1997, 2006, 2014 and extended methods to earthquake early warning for protection of sensitive installations (Xu et al, 2003). In this study we seek to find direct discernment of periodicities in earthquake sequences by adopting wavelet analysis (Grossman & Morlet, 1984).…”

Seismic hazard and risk in Shanghai and estimation of expected building damage

“…The evaluation of Gumbel's third distribution has been used widely to determine extreme magnitude [9,13] because of the physical realistic upper bound at higher magnitudes. The fact that there is a finite limit to the build up of strain energy is an inescapable physical reality [14].…”