This is a type of chart that horizontally scrolls as new data appears. It's used to register the history across time of some data. Commonly used for monitoring as well.
There is no specific name for this type of updating, but it is a form of dynamic time-series plot. At any given time, the plot itself is merely a time-series plot based on a particular set of data; since new data are added as received, it makes sense to say that this is a form of dynamic plot (see e.g., here). The notion of a dynamic plot is broader than this, since it can refer to any kind of updating either by automation or by user input.