A novel technique to quantitatively assess volcanic eruption dynamics is presented. We report on measurements of volcanic eruption velocities with a modified micro radar Doppler anemometer on Stromboli volcano, Italy. The mean vertical eruption velocity recorded during a four day period in late 1996 was around 10 m/s which is somewhat on the small side for strombolian eruptions. However, the activity of Stromboli volcano during this period was very weak explaining the relatively small velocities. The technique used is much better in resolution than older techniques based on static photos and allows a continuous monitoring of the volcanic activity. In addition to the velocity information recorded by the Doppler Spectrum it also contains information on the density of the ejected material and the size distribution of the particles in the volcanic jet.