000002986 001__ 2986
000002986 005__ 20170410103056.0
000002986 0247_ $$2DOI$$a10.5194/se-8-453-2017
000002986 037__ $$aSCART-2016-0021
000002986 100__ $$aVan Noten, Koen
000002986 245__ $$aPath and site effects deduced from merged transfrontier internet macroseismic data of two recent M4 earthquakes in NW Europe using a grid cell approach
000002986 260__ $$c2017
000002986 520__ $$aThe online collection of earthquake reports in Europe is strongly fragmented across numerous seismological agencies. This paper demonstrates how collecting and merging online institutional macroseismic data strongly improves the density of observations and the quality of intensity shaking maps. Instead of using ZIP code Community Internet Intensity Maps, we geocode individual response addresses for location improvement, assign intensities to grouped answers within 100 km2 grid cells, and generate intensity attenuation relations from the grid cell intensities. Grid cell intensity maps are less subjective and illustrate a more homogeneous intensity distribution than communal ZIP code intensity maps. Using grid cells for ground motion analysis offers an advanced method for exchanging transfrontier equal-area intensity data without sharing any personal information. The applicability of the method is demonstrated on the felt responses of two clearly felt earthquakes: the 8 September 2011 ML 4.3 (Mw 3.7) Goch (Germany) and the 22 May 2015 ML 4.2 (Mw 3.7) Ramsgate (UK) earthquakes. Both events resulted in a non-circular distribution of intensities which is not explained by geometrical amplitude attenuation alone but illustrates an important low-pass filtering due to the sedimentary cover above the Anglo-Brabant Massif and in the Lower Rhine Graben. Our study illustrates the effect of increasing bedrock depth on intensity attenuation and the importance of the WNW–ESE Caledonian structural axis of the Anglo-Brabant Massif for seismic wave propagation. Seismic waves are less attenuated – high Q – along the strike of a tectonic structure but are more strongly attenuated – low Q – perpendicular to this structure, particularly when they cross rheologically different seismotectonic units separated by crustal-rooted faults.
000002986 536__ $$aFNRS/$$cPDR/$$fT.0116.14
000002986 594__ $$aNO
000002986 6531_ $$aDid You Feel It
000002986 6531_ $$aEarthquake
000002986 6531_ $$aBrabant Massif
000002986 6531_ $$aLower Rhine Graben
000002986 700__ $$aLecocq, Thomas 
000002986 700__ $$aSira, Christophe
000002986 700__ $$aHinzen, Klaus-G.
000002986 700__ $$aCamelbeeck, Thierry
000002986 773__ $$c453-477$$pSolid Earth$$v8$$y2017
000002986 8560_ $$fkoen.vannoten@observatoire.be
000002986 85642 $$ahttp://www.solid-earth.net/8/453/2017/se-8-453-2017.html
000002986 905__ $$apublished in
000002986 980__ $$aREFERD