M7.1 Quake Hits Japan's 'Silicon Island': TSMC's JASM Halts, Tokyo Electron Inspects — Status of Every Kumamoto Fab

[July 29 update] For the day-after picture — TSMC's gradual restart, confirmed damage at Renesas, and the market reaction — see our day-2 report. Tokyo Electron has since officially reported no major damage, with full operation targeted from the following week and a "minor" earnings impact. This article stands as the record of July 28.

[July 30 update] Three days on, TSMC still has not declared a full recovery — see our day-3 report for why equipment recalibration is taking this long, drawing on the 2016 precedent.

This coverage is also available in Japanese: the day-1 report and the day-2 update.

The Japan Meteorological Agency (JMA) registered the quake at magnitude 7.1 (preliminary) with a depth of about 10 km. Two municipalities, Uki City and Hikawa Town, recorded shindo 7 — the maximum value on Japan's seven-stage seismic intensity scale. Because the quake exceeded the agency's naming criteria (an inland quake of M7.0 or greater with intensity 5+ or higher), the JMA formally named it the 2026 Kumamoto Earthquake (JMA, July 28, 2026). The fab cluster around Kikuyo and Koshi, just north of the epicenter, shook at intensity 5+.

What happened, and how strong was the earthquake?

The main shock occurred at 4:27 p.m. JST on July 28, 2026, in the Kumamoto region of Kyushu, Japan's southwestern main island. The JMA put the magnitude at 7.1 and the depth at about 10 km; both figures are preliminary. Seismologists describe the mechanism as a strike-slip fault rupture similar to the deadly 2016 Kumamoto earthquakes (Nikkei, July 28, 2026). A tsunami advisory for the Ariake and Yatsushiro Seas was lifted at 6:10 p.m. the same day.

The quake also damaged the infrastructure that fabs depend on. The Kyushu Shinkansen suspended service for the rest of the day, expressways closed in 23 sections across three routes, and about 48,000 households in Kumamoto Prefecture lost power as of 5:45 p.m. (Nikkei, NHK, July 28, 2026). Consequently, even undamaged plants face constraints on staffing, logistics and stable power in the days ahead.

Which fabs and plants are affected? (Status as of the night of July 28)

The table below summarizes every confirmed company statement and major-media report. All information reflects the night of July 28; safety inspections on July 29 and beyond may change the picture.

(Nikkei, ANN, Tokyo Electron official release, Nikkan Kogyo Shimbun — all July 28, 2026)

Three caveats matter here. First, Japanese and Taiwanese reports differ on JASM: Japanese broadcaster ANN reported that the fab "halted operations," while some Taiwanese outlets quoted TSMC as expecting no operational impact. The discrepancy most likely reflects timing — an initial evacuation followed by a post-check assessment — but neither version should be treated as final. Second, "no announcement" from Mitsubishi Electric and Renesas does not mean "no impact"; both companies run major front-end fabs in the affected area, and their July 29 statements will be more informative than tonight's silence. Third, the only company that issued a formal disaster release on July 28 was Tokyo Electron, which said it will prioritize safety and inspect both plants before restarting.

Why does Kumamoto matter to the global chip supply chain?

Kumamoto is not a peripheral site. The prefecture concentrates four different layers of the semiconductor supply chain within a 30-kilometer radius.

First, logic manufacturing: JASM, TSMC's first Japanese fab, produces 22/28nm and 12/16nm chips at about 55,000 wafers per month, mainly for Sony's image-sensor logic and Denso's automotive parts. Second, image sensors: Sony's Kumamoto Technology Center makes CMOS image sensors for digital cameras, surveillance and industrial applications, plus microdisplays. Third, power semiconductors: Mitsubishi Electric's Kumamoto works is the mother fab for its silicon power-device wafer processing, and its brand-new 8-inch SiC line in Kikuchi started up only in November 2025. Fourth — and least replaceable — chipmaking equipment: Tokyo Electron Kyushu builds the coater/developers that hold roughly 90% of the global market, and Kumamoto is effectively the only place in the world where they are made.

Consequently, the market reaction focused on TSMC first — its ADRs fell 2.6–3.5% in US premarket trading (Yahoo Taiwan, July 28, 2026) — but the longer-tail risk sits with the equipment and materials layer. A companion article examines which Kumamoto products have backup production sites and which do not.

What does the 2016 precedent say about recovery time?

Kumamoto went through this almost exactly a decade ago. In April 2016, a M6.5 foreshock was followed two days later by a M7.3 main shock, and Sony, Renesas, Mitsubishi Electric and Tokyo Electron Kyushu all stopped production (EE Times Japan, April 2016).

The recovery times split sharply by plant type. Tokyo Electron Kyushu, an equipment-assembly operation, resumed production in stages after about 10 days. By contrast, Sony's Kumamoto fab — a cleanroom wafer plant — needed about 1.5 months to restart wafer input and about 3 months to recover fully, which disrupted the digital-camera supply chain worldwide. Sony later concluded that its business-continuity plan had been insufficient and revised it (Kumamoto Nichinichi Shimbun). The rule of thumb from 2016 is therefore: equipment plants recover in weeks; front-end fabs recover in months.

However, 2026 is not 2016. Renesas demonstrated in 2016 that its post-Fukushima BCP worked, restarting faster than peers. Every major player has since reinforced buildings and buffer inventories, and JASM's fab was built after 2016 to current seismic standards. The precedent defines the worst case better than it predicts the likely one.

What should you watch next?

Watch three things, in order. First, inspection results from July 29 onward — especially the first statements from Mitsubishi Electric, Renesas and Sony, none of which had spoken as of July 28 night. Second, aftershock activity: the JMA held two press conferences on July 28 and warned that quakes up to intensity 7 could occur for about a week, especially within 2–3 days. In 2016, the largest quake came second; companies will not fully restart lines while that scenario remains open. Third, the Tokyo market open on July 29, which will deliver the first domestic price discovery for Tokyo Electron, Sony, Renesas and Disco.

Key takeaways

• A M7.1 (preliminary) earthquake — officially named the 2026 Kumamoto Earthquake — struck at 4:27 p.m. JST on July 28, registering Japan's maximum seismic intensity of 7; the Kikuyo/Koshi fab cluster shook at intensity 5+.
• JASM (TSMC) evacuated and halted operations; Sony evacuated both image-sensor fabs; Tokyo Electron Kyushu suspends both plants on July 29 for inspection; TOPPAN and Fujifilm Kyushu stopped production. No injuries or major damage had been confirmed as of July 28 night.
• Mitsubishi Electric, Renesas and Sanken had made no announcements — which is not the same as confirming no impact.
• The 2016 precedent: equipment assembly recovered in about 10 days, while Sony's front-end fab took about 3 months. Post-2016 reinforcement and BCPs mean the worst case is not the base case.
• The JMA warns of intensity-7-class aftershocks for about a week. Inspection results, aftershock activity and the July 29 Tokyo open are the three things to watch.