Online Material: Tables of questions and answers of the macroseismic questionnaire, score matrices, and a figure showing a macroseismic field example. Macroseismic investigation with data collected through web‐based questionnaires is today routinely applied by most important seismological institutions, such as the U.S. Geological Survey (http://earthquake.usgs.gov/earthquakes/dyfi/; last accessed December 2014), British Geological Survey (http://www.earthquakes.bgs.ac.uk/questionnaire/EqQuestIntro.html; last accessed December 2014), European‐Mediterranean Seismological Centre (http://www.emsc-csem.org/Earthquake/Contribute/choose\_earthquake.php?lang=en; last accessed December 2014), Schweizerische Erdbebendienst (http://www.seismo.ethz.ch/eq/detected/eq\_form/index_EN; last accessed December 2014), Bureau Central Sismologique Francais (http://www.seisme.prd.fr/english.php; last accessed December 2014), and the New Zealand GeoNet project (http://www.geonet.org.nz/quakes/; last accessed December 2014). The wide diffusion of Internet and the citizen collaboration (crowdsourcing) allow documentation of information on seismic effects and production of a macroseismic field with low costs and almost in real time. Transformation from qualitative information (as given by questionnaires) to numerical quantification is a crucial issue. In the traditional evaluation of intensity, experts used to work through a complex comparison of effects basically driven by personal experience. The major problem with this approach concerns the difficulty in verifing and reproducing the evaluation process due to the lack of a detailed explanation of the employed workflow and to the large variability of possible cases. On the other hand, an automatic method for the estimation of macroseismic intensities needs to be completely well defined and specified in order to be reproducible and verifiable. For these reasons, this paper presents a comprehensive explanation of our intensity assessment method. A useful automatic method for intensity assessment should be computationally fast and strictly follow the macroseismic scales. To meet these requirements in 2010, we proposed a method that firstly quantified the effects using additive scores associated with each answer of the questionnaire item and then determined an intensity estimate for each questionnaire (Sbarra et al. , 2010). After …