Event relatedness assessment of Twitter messages for emergency response.

•A novel method to assess the degree of relatedness of Twitter messages to a specific event of interest and identify the event-related tweets in a timely and accurate manner.•Defining the concept of “event related term-classes” that are utilised as a template to identify and detect the tweets which are potentially related to the targeted event.•Effective filtering and data cleaning techniques to facilitate and accelerate Twitter data analysis.•An evaluation of the method in terms of accuracy, timeliness and reliability.