The phrase "are slightly deeper" is correct and usable in written English.
It can be used when comparing the depth of two or more objects, concepts, or situations, indicating a minor difference in depth.
Example: "The new wells are slightly deeper than the previous ones, allowing for better water access."
Alternatives: "are a bit deeper" or "are somewhat deeper".
The findings showed that chloride penetration was slightly deeper in recycled concretes, while no alterations were observed in the relationship among durability indicators.
Compared to the nineteen-eighties, the current recession is slightly deeper in terms of G.D.P. What is very different this time is the pattern of unemployment.
Differences, while they emerge, are subtle: the timbre of their voices (Nate's is slightly deeper), the pattern of their Alexander Olch bow ties, the color of their Ben Sherman shirts — both in plaid.
The initiation point of the rupture was slightly deeper than the relocated hypocenter by Yoshida et al. (2016).
The source depth of 9.2 km prior to the climax event is slightly deeper that those during (8.3 km) and after (8.2 km) this event.
Region 3 corresponds the area where the eastern edge of the KPR bounds the deepest part of the Shikoku Basin and the KPR topography is slightly deeper and narrower than in other regions.
The source depth for the magma effusion stage is estimated to have been slightly deeper than the source for the sub-Plinian eruptions, although these estimates are within error.
The hypocenter depth of the main shock estimated by the Japan Meteorological Agency is slightly deeper than the neutral plane between down-dip compression (DC) and down-dip extension (DE) stress zones of the double-planed seismic zone.
We used normal 12 V electric motors designed for use on manned vessels, so their drafts were slightly deeper, and unsuitable for use at depths of less than 1 m.
