A strong 7.5 quake strikes Japan’s Tohoku region! Jiexia, Kioxia’s Iwate plants, account for 4% of global NAND capacity, raising alarms over the memory supply

Around 4:53 p.m. on April 20, a sudden strong earthquake with a magnitude of 7.5 struck Japan’s Tohoku region. The maximum seismic intensity of 5 was observed in Aomori Prefecture, and tsunami warnings were also issued for Hokkaido and the Pacific coast, with an estimate that the worst case could bring waves as high as 3 meters. Since the Tohoku region itself is one of Japan’s major semiconductor hubs, this earthquake is not just a straightforward natural disaster—it has quickly increased market concerns about disruptions to the memory supply chain and regional electronics manufacturing clusters.

Market expects Geisha Iwate plant to shut down for inspection

Meritz Securities said the earthquake’s epicenter was located about 174 kilometers offshore, and seismic intensities of 2 to 5 were observed in many inland areas by the Japan Meteorological Agency. The site most closely watched by the market is Kioxia’s NAND Flash plant in Kitakami, Iwate Prefecture. Because Kitakami also recorded a seismic intensity of 4, and under the semiconductor industry’s usual risk-control mechanisms, outside expectations are that the plant area will likely shut down for inspections first and assess needs such as wafer scrap, rework, and equipment calibration. The subsequent restart pace will become a key variable affecting NAND supply.

Kioxia’s Iwate plant is particularly sensitive because it is not an edge-capacity facility. According to Meritz Securities data, as of April 2026, global NAND capacity is about 1.337 million wafers per month, of which Kioxia’s Iwate Fab 1 accounts for about 55,000 wafers per month—about 4% of global capacity. Once the earthquake leads to longer shutdown time, damage to yields, or an increase in scrap volume, it will inevitably influence market expectations for both NAND spot and contract markets.

Japan’s semiconductor hub in Tohoku—supply chain map revealed

What is even more worth noting is that Iwate is the most sensitive link in the Tohoku semiconductor supply chain. In addition to Kioxia, it also gathers Japan Semiconductor, Amkor, Rohm コーア (Rohm Core), Misuzu Semiconductor, Screen’s Soku Industrial Iwate Plant, as well as Kurita / Kurita Clean Surface Technology, and Tokyo Electron Technology Solutions’ Tohoku office, among other sites, covering front-end processes, back-end packaging, equipment, and cleaning technologies.．

Source: @phithetasigma

Looking at the broader regional supply-chain landscape, Japan’s six Tohoku prefectures were originally important bases for Japan’s electronic and semiconductor manufacturing. In Miyagi Prefecture, manufacturers include Sony Semiconductor Manufacturing’s Shiraishi Kurayama Technical Center, LAPIS Semiconductor’s Miyagi plant, RS Technologies, and Tokyo Electron Technology Solutions’ Miyagi facilities.

Yamagata Prefecture also has Tohoku Epson, Stanley Electric’s Yamagata plant, Sony Semiconductor Manufacturing’s Yamagata Technology Center, Renesas Electronics’ Yonezawa plant, ASE Japan, and other sites.

In Aomori Prefecture, you can see Fuji Electric Tsugaru semiconductor, Japan Micronics’ Aomori plant, and ULVAC Tohoku; in Akita Prefecture, there are companies such as Tianma Japan’s Akita plant, DOWA Semiconductor Akita, Inspec, and more; Fukushima Prefecture is also home to sites such as Hitachi Power Device’s Narashino plant, Alps Alpine, and Sony Semiconductor’s Aizu facilities.

Therefore, the risk from this earthquake is not only whether Kioxia’s Iwate Fab 1 will temporarily shut down, but also that it may simultaneously compress future supply increases. Originally, Kioxia’s Iwate Fab 2 was expected to start partial mass production in the second quarter of 2026, but after this strong earthquake, whether equipment introduction, plant facility verification, and production-line ramp-up schedules are delayed has become the market’s new focus. If the expansion pace for Fab 2 slows down, the incremental NAND supply that the market originally expected will likely be reduced as well, further deepening expectations of tighter supply.

This article, “Tohoku Japan 7.5 strong earthquake! Kioxia’s Iwate plant accounts for 4% of global NAND capacity, memory supply alarm raised,” first appeared in chain news ABMedia.