This paper presents a joint analysis of instrumental and macroseismic data regarding the 19 July 2019, Greece Mw5.1 earthquake occurred west of Athens. This earthquake ruptured a blind, south-dipping normal fault, 23 km WNW of the center of Athens, while its relocated epicentre lies in close vicinity to the one of the 1999 Mw6.0 earthquake. The maximum macroseismic intensity of the 2019 mainshock reached IEMS98 = 7.5. Scarce damage and intensities up to 5–6 were reported in the epicentral area. Higher intensities were observed at larger distances, 12–15 km east and ESE of the epicentre, alongside the banks of Kifissos River, likely related to ground motion amplification due to soft alluvial formations. Similar selectivity of increased ground motions to the east of the epicentre with respect to other azimuths, also observed during the 1981 and 1999 earthquakes, supports eastward rupture directivity of the 2019 mainshock, an effect that is possibly common for the region’s fault system. Damping of seismic effects was observed east of Aegaleo Mountain, a structure suggested to impose a stopping phase in the time histories of the 1999 and 2019 earthquakes (Fig. A1).

Sources containing descriptive information on earthquake effects in Greece from the period 1800–1899 are analysed and EMS-98 macroseismic intensities are assigned, aiming at the enrichment of the number of macroseismic datapoints contained in the Hellenic Macroseismic Database (HMDB.UoA). Based on the information provided by the analysis, intensities were re-assigned for all events reported in the sources. Compared to the MDPs presented in the Hellenic Macroseismic database, the total number of MDPs from the present study is more than double. Similar procedure was applied to the 19th century Samos and surrounding areas earthquakes including all macroseismic intensity degrees. For the case study of Samos, two macroseismic intensity data sets are presented: the damaging (IEMS98 > 6) and the non-damaging ones. The macroseismic parameters of one new earthquake were determined and the seismic history of the island showed that two earthquakes, probably similar to the 30 October 2020 Samos event, occurred in the 19th century. New earthquakes improve the seismic history and increased MDPs number allow for more accurate parameters assessment.