Apostolos Agalos

• Ph.D. Seismologist Μ.Sc. Geophysicist
• Secondary Science Teacher at Ministry of Education, Greece

The seismic sequence at the southern part of Zakynthos Island (Ionian Sea, Western Greece) during April and May of 2006 is investigated. It consists of four moderate earthquakes (5.3 ≤M w≤ 5.7) that were followed by significant seismic activity. Source parameters of the significant events were determined using two different techniques. Teleseismic...

On 26.1.2014 and 3.2.2014 two strong earth-quakes of M w 6.0 and M w 5.9 ruptured the west-ern Cephalonia Isl., Ionian Sea (Greece), at the SSW-wards continuation of the Lefkada segment of the Cephalonia Transform Fault Zone (CTFZ), causing considerable damage and a variety of ground failures. High-preci-sion relocation of the aftershocks implies t...

On August 24, October 26 and 30, 2016, Central Apennines (Italy) were hit by three shallow, normal faulting very strong earthquakes rupturing in an NW–SE striking zone. Event 3 (Norcia) occurred between event 1 (Amatrice) at the SE and event 2 (Visso) at the NW of the entire rupture zone. The rupture histories of the three events, as revealed by te...

On July 1, 2009, a Mw 6.45 earthquake ruptured south of Crete Island (Greece) along the Hellenic Arc triggering a local tsunami. Eyewitness reported the tsunami from Myrtos and Arvi (south-eastern Crete) and from the north of Chrisi Islet, located to the southeast of Crete. The earthquake occurred offshore, about 80 km south of Crete, where routine...

The tsunamigenic potential of an earthquake depends on its size, source depth and focal mechanism. The Hellenic Subduction Zone (HSZ) has been selected in the paper to study this important issue. The HSZ was ruptured by 11 strong (Mw6.0) earthquakes in the time period 2009–2023. One earthquake ruptured onshore but only three out of ten offshore ear...

This work investigates the effect that earthquake fault model types and properties have on the numerical modelling of tsunami generation and propagation. This is done using a 2DH post-Boussinesq model, properly adapted to represent tsunami waves generated by dynamic bed deformations due to dip-slip faulting. Model runs are performed for fault model...

Three strong earthquakes ruptured the northwest Thessaly area, Central Greece, on the 3, 4 and 12 March 2021. Since the area did not rupture by strong earthquakes in the instrumental period of seismicity, it is of great interest to understand the seismotectonics and source properties of these earthquakes. We combined relocated hypocenters, inversio...

The NEAM Tsunami Hazard Model 2018 (NEAMTHM18) is a probabilistic hazard model for tsunamis generated by earthquakes. It covers the coastlines of the North-eastern Atlantic, the Mediterranean, and connected seas (NEAM). NEAMTHM18 was designed as a three-phase project. The first two phases were dedicated to the model development and hazard calculati...

Significant seismicity anomalies preceded the 25 October 2018 mainshock (Mw = 6.8), NW Hellenic Arc: a transient intermediate-term (~2 yrs) swarm and a short-term (last 6 months) cluster with typical time-size-space foreshock patterns: activity increase, b-value drop, foreshocks move towards mainshock epicenter. The anomalies were identified with b...

With the strong 26 November 2019 earthquake that struck western Albania, several buildings collapsed, causing 51 casualties, mainly in the areas of Durrës and Thumanë. The destruction is attributed to several factors, including strong ground motion (maximum peak ground acceleration 192 cm= s 2 in Durrës), soil liquefaction, site amplification, poor...

The M 7.5 earthquake that hit the island of Sulawesi on 28 September 2018 occurred on a long (> 150 km) fault, striking mostly N-S and was characterized by a prevailing strike-slip focal mechanism. The hypocenter of the earthquake was located some 40 km NNE of the northern end of the Palu Bay, a narrow semi-closed basin, approximately 30-km long an...

On 25 October 2018 a Mw6.8 earthquake occurred in the South Ionian Sea. Fault plane solutions produced by various centers revealed a rupture mechanism combining thrust fault movement with significant strike-slip component. Only moderate damage was reported mainly from Zakynthos Isl. due to that the earthquake epicenter was placed offshore about 55...

On 28th September 2019 an earthquake of magnitude Mw=7.5 characterized by a prevalent strike-slip mechanism and with an epicenter located to the north of Palu Gulf, island of Sulawesi, Indonesia. The earthquake was followed by a tsunami that struck with run-up height that reached values exceeding 6 m in the area of Palu, located in the southern end...

Ten years after the occurrence of the Andravida earthquake (2008) several aspects were investigated, including its connection to neighboring spatiotemporal clusters in the following years. On 8 June 2008 at 12:25 GMT a large earthquake (M w =6.4) occurred NE of Andravida (Greece) in an area characterized by relatively low seismicity. Nevertheless,...

On 12th June and 20th July, two major earthquakes occurred in the Aegean Sea of Magnitude Mw. 6.3 and Mw. 6.6 that generated both tsunamis along the coasts of Greece and Turkey. Although of limited magnitude, the two events raised several questions on the preparedness of Mediterranean countries to face such events that are considered of low probabi...

On 17 November 2015 a Mw6.5 earthquake ruptured offshore Lefkada Isl. in Ionian Sea, Greece, causing two victims, damage and ground failures particularly in the SW part of the island, which is consistent with the ground deformation pattern shown by InSAR analysis. Fault plane solutions released by CMT, NOA and other institutes are consistent indica...

In the major Atlantic-Mediterranean seismic fracture zone, extended from Azores islands in the west to the easternmost Mediterranean Sea in the east, including the Marmara and Black Seas, a number of 22 tsunamigenic zones have been determined from historical and instrumental tsunami documentation (Papadopoulos et al., 2014). Although some tsunamis...

Broadband waveforms from the Hellenic Unified Seismic Network (HUSN) and strong motion records from the National Observatory of Athens (NOA) network are used for rapid determination of moment tensors for earthquakes (M>3.6) that occur in Greece and the surrounding areas. The inclusion of strong motion stations/records at local distances provides re...

On 18 January 2010, 15:56 UTC, a M w = 5.1 (National Observatory of Athens; NOA) earthquake occurred near the town of Efpalion (western Gulf of Corinth, Greece), about 10 km to the east of Nafpaktos, along the north coast of the Gulf. Another strong event occurred on 22 January 2010, 00:46 UTC with M w = 5.1 (NOA) approximately 3 km to the NE of th...

Greece is characterized by high seismicity mainly due to the collision between the European and the African lithospheric plates. During the recent years strong earthquakes occurred in regions with different seismotectonic regimes. Moment tensor inversion was applied to determine the source properties, as well as the dynamic processes of these event...

The rapidly opening rift of the Corinth Gulf is dominated by normal faults and high level of seismicity. Recently, an important number of moderate earthquakes occurred in the western part of the gulf and the surrounding region. In April 2007, 4 events with magnitudes 5.0-5.2 occurred near Trichonis Lake, in SE Aitoloakarnania. A temporary network o...

The source parameters of all the moderate and strong events that occurred in the broader area of Zakynthos Island for the period 1997–2009 are determined using two different techniques depending on epicentral distance. For the strong events we employed teleseismic body-wave modeling between 30° and 90°, while for moderate events a regional moment t...

The seismic hazard of Greece has been studied mainly through methods using maximum expected magnitude and peak ground acceleration. However, few studies that have taken into account macroseismic intensity data appear in the bibliography. In this paper, a seismic hazard analysis based on Gumbel's approach to PSHA for the Ionian Islands Corfu, Zakynt...

The Corinth Rift in Central Greece is one of the most seismically active regions in Europe characterized by normal faulting in an approximate E-W direction. Two moderate earthquakes, with moment magnitudes 4.7 and 4.5 respectively, occurred in NW Peloponnesus (Greece) on February and triggered a seismic swarm. Focal mechanisms of these events were...

Many moderate size earthquakes occur in the broader area of Greece which are recorded by the Seismological Network belonging to the Department of Geophysics and Geothermics of the University of Athens. These records are combined with data recorded from other Institutes in order to calculate source parameters. An inversion approach is applied, using...

Southern Greece is dominated by the presence of the Hellenic Arc, whose formation is the result of the convergence between the Eurasian and Africa plates in an approximately NNE-SSW direction with a rate of about 2 cm/year. The broader area of Peloponnesus, located in Southern Greece, hosts since the antiquity a significant number of large earthqua...

On February 4th, 2008, two moderate earthquakes, with moment magnitudes 4.7 and 4.5 respectively, triggered a seismic swarm in NW Peloponnesus, Greece. The epicentral area is close to the Chalandritsa fault which is located in the transition between the normal faulting zone of the southern Corinth rift and a strike-slip faulting zone which characte...

Seismic moment tensors are estimated for earthquakes offshore Northern California and Greece using inversion of regionally recorded broadband seismograms. This study includes inversion results for the strongest events that occurred inside the Gorda plate and near the Mendocino triple junction from 1991 to 2005. The regional results are in good agre...

Two M6+ events occurred 15–20 km apart in central Greece on April 20 and April 27, 1894. We identify the April 27, 1894 rupture (2nd in the sequence) with the Atalanti segment of the Atalanti Fault Zone because of unequivocal surface rupturing evidence reported by Skouphos [Skouphos, T., 1894. Die swei grossen Erdbeben in Lokris am 8/20 und 15/27 A...