Japan Geography Quiz | Reading Kyūshū and Okinawa Plains, Volcanoes, Coasts, and Island Chains, Set 7

The Chikushi Plain spreads through the basins of the Chikugo and Yabe rivers in southern Fukuoka, and both rivers empty into the Ariake Sea on the prefecture's southwest side. The Fukuoka Plain faces Hakata Bay, while the Nōgata Plain belongs to the Onga River basin, so the plain, rivers, and sea must match as a set.

The inner Ariake Sea has a large tidal range. Fine sediment carried by the Chikugo and other rivers is reworked by tides and tidal currents, producing extensive tidal flats of soft mud. A steeply deepening seabed and limited sediment supply are the opposite of the conditions that create broad muddy flats.

The Shimabara Peninsula lies in southeastern Nagasaki and was shaped by the activity of Unzen Volcano. It is bordered by the Ariake Sea and Tachibana Bay. The Kunisaki Peninsula is in Ōita, while the Satsuma and Ōsumi peninsulas are in Kagoshima, and their listed volcanoes and waters do not match.

In the Aso Caldera, the caldera floor spreads around the central cone group, and the caldera wall and outer rim enclose it. A caldera is not simply one giant crater; it includes several landform elements, from its interior lowland to the surrounding high ground.

On Ōita's eastern coast, the Kunisaki Peninsula projects into the Seto Inland Sea in the north, and Beppu Bay indents westward to its south. Farther south beyond Saganoseki, an intricate ria coast faces the Bungo Channel. Placing Beppu Bay north of the Kunisaki Peninsula reverses their positions.

The Ōyodo River flows north through the Miyakonojō Basin, passes through a narrow reach between the Hyūga and Wanitsuka mountains, enters the Miyazaki Plain, and empties into Hyūga-nada. The Miyazaki Plain is downstream and does not come before the Miyakonojō Basin.

Southern Kyūshū's extensive shirasu plateaus formed when pyroclastic-flow deposits and other ejecta from the massive eruption that produced the Aira Caldera about 30,000 years ago covered a broad area. Their material and formative process differ from those of a river-built alluvial plain.

The conditions identify Yakushima. Most of the island is granite, and it has a large elevation range from the coast to high mountains. Consequently, vegetation shows clear vertical zonation with elevation, from subtropical environments in the lowlands to cool-temperate environments at high elevations.

In the source's usage, the Ryūkyū Islands form an arcuate chain about 1,200 km from north to south at the southern end of the Japanese archipelago. They include the Tokara and Amami islands of Kagoshima and the Okinawa and Sakishima islands of Okinawa Prefecture, so the chain crosses a prefectural boundary.

Broadly, Okinawa Island divides into a mountainous north and a relatively flat central-southern area, where the Shimajiri Group and Ryūkyū Limestone are widespread. Limestone also occurs in northern areas such as the Motobu Peninsula, so it would be too absolute to claim that northern Okinawa has no limestone at all.