The phrase "an indication of the depth" is correct and usable in written English.
It can be used when discussing measurements, levels, or the extent of something, often in a metaphorical or analytical context.
Example: "The survey results provide an indication of the depth of public concern regarding environmental issues."
Alternatives: "a sign of the extent" or "a measure of the level".
Each prism was snapped in half, one half was tested using Phenolphthalein indicator, to give an indication of the depth of carbonation, and subsequently used for sorptivity tests, while the other was used for compressive strength testing.
Those matches, the report said, might be only an indication of the depth of the problem.
That may simply be an indication of the depth of the recession.
There, upon closer inspection, was another name and, perhaps, an indication of the depth of Mr. Gelman's fixation.
But a Treasury official's note on 28 October 1982 to the then chief secretary to the Treasury, Leon Brittan, gave an indication of the depth of internal opposition Howe and Thatcher faced.
A meeting on Thursday evening of doctors in the BMA's London branch is expected to give an indication of the depth of hostility towards the changes, which will see commissioning of healthcare handed to GPs.
He said in an interview that interest in the event was "an indication of the breadth and depth of Jerry Brown's support here early in the race".
Both are decent players, yet those numbers are an indication of the lack of depth in the domestic game's bowling, and that surely plays a part in England's relative paucity of resources at international level.
It is an indication of the strength in depth at Pittodrie nowadays that former Caley Thistle and Scotland midfielder Barry Robson was Jack's replacement.
That the 2012 Supreme Novice Hurdler Cinders And Ashes and Countrywide Flame, last year's Triumph Hurdle winner, are outsiders is an indication of the strength in depth here.
Integrating both Gravity and MT interpretation, the model supports that beneath the surface manifestations (hot springs), low-density and low-resistivity geophysical anomaly is present which might be an indication of the existence at depth of a geothermal reservoir.
