Characterizing Twitter users behaviour during the Spanish Covid-19 first wave

People use Online Social Media to make sense of crisis events. A pandemic crisis like the Covid-19 outbreak is a complex event, involving many aspects of the social lives on many temporal scales. Focusing on the Spanish Twittersphere, we characterize users activity behaviour across the different phases of the Covid-19 first wave. By performing stepwise segmented regression analysis and Bayesian switchpoint analysis on a sample of Spanish Twittersphere users timeline, we observe that generic Spanish Twitter users and journalists experience an abrupt positive relative increment of their tweeting activity between March the 9th and the 14th, in coincidence with control measures being announced by regional and State level authorities. On the contrary, politicians follow a completely endogenous dynamic determined by institutional agenda.