The phrase "a vast zone" is correct and usable in written English.
It can be used to describe a large area or region, often in a geographical or metaphorical context.
Example: "The researchers discovered a vast zone of biodiversity in the remote rainforest."
Alternatives: "a large area" or "an extensive region".
Nor do we want to see a weak China, beset by internal conflicts and social dislocation, becoming a vast zone of instability in Asia.
Sulawesi is the largest and oldest island within Wallacea, a vast zone of oceanic islands separating continental Asia from the Pleistocene landmass of Australia and Papua (Sahul).
At the beginning, no radiographic manifestations are seen, but in some cases a vast zone of necrotic bone can be seen on MRI, larger than what could be expected.
As for the Iraq war, the war the Lib Dems stood against, the war that has made the Middle East into a vast zone of horror, it was in the interests of both the Tories and Labour to not mention it.
The principal results were a vast zone of partial melts beneath the Altiplano at latitude 21°S at mid and lower crustal depths, and the highly conductive West Fissure Zone beneath the Precordillera, explained by rising saline fluids from the deeper crust or even the downgoing slab (Echternacht et al.1997).1997
In the case of a vast failure zone, tightly spaced short rockbolts are installed to establish an artificial pressure arch within the failure zone and long cables are anchored on the natural pressure arch.
Today, the Expo area is a vast construction zone.
Fertilizer runoff is responsible for a vast "dead zone," an oxygen-depleted region where little or no sea life can exist, in the Gulf of Mexico.
Japan has offered to help India develop a vast industrial zone, stretching 1,500km 9300 miles) from Delhi to Mumbai, which could become a hub for Japanese manufacturers.
In the country's geographic heartland is a region known as Najd ("Highland"), a vast arid zone that until recent times was populated by nomadic tribes.
Philippine officials secured for them a vast protected zone in which they lived quietly for nearly 15 years until the departure of the former President, Ferdinand E. Marcos.
