**4. PGV and intensity**

Since the beginning of MSS recording, the macroseismic intensities of 16 earthquakes in the area of the MSS-network were evaluated according to EMS-98 by the Seismological Service of ZAMG. These intensities were assigned to macroseismic data points corresponding to municipalities. We relate each macroseismic data point to PGV values recorded within a circumference of 5 km. In total 120, PGV intensity pairs were found by this procedure.

The maximum epicentral intensity V was assigned for a magnitude ML = 3.7 earthquake with PGV up to 8.44 mm/s. The minimum PGV associated with intensity ≥ II amounted PGV = 0.05 mm/s. On the other hand, we observed PGV values up to 0.42 mm/s related to earthquakes with no reports about felt ground shaking. The number of PGV values, binned to PGV classes, is opposed for 'felt' and 'not felt' in **Figure 6a**. The number for 'felt' overtakes 'not felt' from the class 0.03–0.1 mm/s to the class 0.1–0.3 mm/s. As a first estimate, we set PGV = 0.1 mm/s as the lower valueof felt earthquakes in exceptional instances (higher floors, night time, at rest, etc.), or with intensity II.

**Figure 6b** shows the cross plot of intensity over PGV. The scatter of PGV within intensity classes is considerable and exceeds, in part one decade. Preliminarily we assume a non-linear relation between the logarithm of PGV and intensity. According to the macroseismic detection threshold derived before, the relation is fixed to PGV = 0.1 mm/s at intensity II. The PGV values corresponding to the isoseismals III, IV and V are 0.3 mm/s, 1.0 mm/s, and 10 mm/s. This correlation allows for the interpretation of the corresponding contours in our PGV maps (**Figure 5d**) as isoseismals.

The estimate of macroseismic intensity from instrumental data and vice versa is an important issue for the preparation of shake maps (e.g., https://earthquake.usgs. gov/data/shakemap/). These maps provide just in time information about the area and magnitude of ground shaking of an earthquake and its effect on human perception as well as the intactness of infrastructure derived from instrumental observatory data. In principle, we attempt the same procedure with our PGV contour maps. However, the correlations implemented worldwide differ significantly from our relation (e.g., [9]). The attenuation relation used by the Swiss Seismological

#### **Figure 6.**

**Figure 4.**

**Figure 5.**

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*PGV/SA, (d) contouring PGV/SA by Kriging.*

*center of the MSS-network, 14th June 2019.*

*Earthquakes - From Tectonics to Buildings*

*Sequence of visualizations of the trigger status of Delaunay triangles during the ML = 2.5 earthquake near the*

*Visualization of the ML = 2.5 earthquake near the center of the MSS-network, 14th June 2019; (a) coloring the Voronoi regions according PGV, (b) contouring PGV by Kriging, (c) coloring the Voronoi regions according*

*(a) Frequency of PGV values of 'not felt' versus 'felt' earthquakes recorded at MSS stations between October 2017 and October 2020; (b) intensity (EMS-98) over PGV for the same data set; gray line shows a preliminary PGV-intensity relation.*

Service for the shake maps (http:\\shakemapa.ethz.ch; visited on 23th October 2020) mimics ours. PGV = 0.8 mm/s, 3 mm/s and 9 mm/s corresponds to intensities II – III, IV, and V. PGV < 0.2 mm/s are classified as 'not felt'.
