"fathom the depth" is a correct and usable phrase in written English.
It means to understand or comprehend the true meaning or extent of something. You can use it in a formal or poetic context, such as in a speech, essay, or poem. Example: As I gazed into the endless ocean, I struggled to fathom the depth of its vast and mysterious depths.
And you begin to try to fathom the depth of grief that convulsed a nation.
We can hardly fathom the depth of our dependence on government, and pretend we are bold individualists instead.
Le Clos's disbelief was plain and he only seemed able to fathom the depth of his victory when Phelps eventually paddled across the lanes to congratulate him.
Nor can I fathom the depth of anguish felt by his family, who have tirelessly worked to win his freedom over the past year.
Clinton advisers gritted their teeth Tuesday night as they dissected exit polls and other data to try to fathom the depth of Mrs. Clinton's political vulnerabilities.
Sophie Okonedo's performance as Maya was thrilling this week as the agonised detective trying to fathom the depth of her husband's betrayal, trying to stomach each poisonous morsel she is forced to swallow.
… Even before the hurricane struck on the weekend of Aug. 26, many in Houston were beginning to fathom the depths of the area's flood dangers.
Such effects form the basis of ultrasound systems used to fathom the depths of lakes and waterways and to locate fish.
But when our experience of the wild world shrinks, we no longer fathom the depths of our own words; language loses its lustre and vividness.
He says something like: 'No plumbline can fathom the depths of my faithlessness – now fuck off.'" It is what Macfadyen ultimately loves about the character: "He doesn't buy any superstitious claptrap.
To fathom the depths, she read books; the walls of her house in Maine are lined with them, crammed between baskets and trays filled with sea glass and seashells and sea-smoothed stones.
