How to interpret an Eigen Value vs Speed Graph

I was able to plot this graph finally using Matlab and the data is for a 2-wheeler straight line event. This graph stands for Eigen Value vs Speed. I want help in interpreting this graph and relate it to capsize, weave and wobble. the graph i am referring ot is also attached and  the curves in that is pretty obvious and easier to interpret. 

I have the data for damping ratios, natural frequency as well.

Any idea how to define which curve stands for which type of instability.

Regards

Draucis