Extensional tectonics after the Miocene – probably during the Pliocene – produced the current graben-and-horst structure, with the graben (today's plain) being formed as a pull-apart basin.

Finally, today's plain is covered by a thick layer of alluvium, several hundred meters deep.

The Simav fault is very deep – it has a slip of over 1,000 m – and this allows heat to rise from deeper in the earth's crust, which forms the hot springs in the area.

[9] Overall, agriculture and animal husbandry employ more people than any other sector in Simav district.

[10]: 536 Greenhouse-based agriculture takes place over about 510 decares in Simav district, of which about 360 are heated (using geothermal energy) and 150 are unheated.

Chestnut cultivation takes place over a large forested area on the northern foothills of Mt.

Simav district also has one of the largest livestock markets in the region; it is held on Tuesdays and draws business from various provinces such as Bursa, Istanbul, Balıkesir, Afyon, Uşak, and Manisa.

[9] This is sold under the brand Westboard OSB and is mainly used to supply the construction and packaging sectors.

[10]: 536 Food processing in Simav district includes production of halva and herbal tea.

Historically, the mats were exported to places like Aydın, Denizli, Manisa, İzmir, and Balıkesir.

However, mat weaving went into a serious decline after Lake Simav was dried up in the 1960s, and the craft is almost extinct locally as of 2019.

[9] In the village of Bahtıllı, some 20 km from Simav town, women also contribute to the family economy by hand-weaving and embroidering things like aprons, when not involved in agriculture or animal husbandry.

The aprons are decorated with various floral or geometric designs, with common motifs including carnations and the tree of life.

Local women also make fabric waist ties for commercial purposes.