To find the difference in elevations between the lava chamber and the top of the smoke plume, we need to consider both depths and heights relative to the surface.
- The lava chamber is located 25 km below the surface. This can be represented as -25 km.
- The smoke plume rises 30 km above the surface. This can be represented as +30 km.
To find the difference in elevation, we will calculate the elevation of the plume relative to the lava chamber:
\[ \text{Difference in elevation} = \text{elevation of plume} - \text{elevation of chamber} \] \[ = 30, \text{km} - (-25, \text{km}) \] \[ = 30, \text{km} + 25, \text{km} \] \[ = 55, \text{km} \]
Therefore, the difference in elevations is 55 km.