While everyone is watching the oil bust, there is another bust going on — one for natural gas.

Before there was a boom in oil production in the United States, there was the "shale gas revolution." That is where we all became familiar with terms like "fracking." And the Marcellus, Haynesville, and Barnett Shales were famous long before the Bakken or Permian.

The surge in natural gas production crashed prices, fueling a huge increase in activity in petrochemicals and causing a major switch from coal to natural gas in the electric power industry. Aside from a few brief moments (such as the winter of 2014), natural gas has mostly traded around $4 per million Btu (MMBtu) or lower since the financial crisis of 2008.

But unlike oil, the boom in shale gas did not stop with plummeting prices. U.S. natural gas production continued to climb. For example, production from the prolific Marcellus Shale – which spans Pennsylvania, West Virginia and Ohio – skyrocketed from less than 2 billion cubic feet per day (bcf/d) in 2009, to a record-high of over 16.5 bcf/d this year. And the dramatic ramp up in production occurred over several years when prices were extremely low.

Much of that has to do with the huge innovations in drilling techniques, including fracking and horizontal drilling, which allowed for production to remain profitable despite the downturn in prices. But some of the credit also goes to drillers searching for more lucrative natural gas liquids and crude oil. Dry natural gas is produced in association with oil. With oil prices extremely high, especially in the period between 2010 and 2014, drillers continued to produce natural gas even if they were looking for oil.

So only after oil prices busted did natural gas production start to slow down. In fact, while the markets are eagerly watching for declines in oil production, few are noticing that natural gas production is also declining. The EIA reports that in October, several of the largest shale gas regions will post their fourth month in a row of production declines. With a loss of around 208 million cubic feet per day expected in October, the four-month drop off will be the longest streak of losses in about eight years.

It is no surprise that the Eagle Ford will represent the largest losses, with a decline of 117 million cubic feet per day expected in October. That is because oil is a much more prized commodity in South Texas, so the decline is largely attributable to disappearing crude oil rigs.

While U.S. shale gas remained resilient through several years of low natural gas prices, the collapse in oil prices are finally putting an end to the boom.