A major earthquake with a magnitude of 7.1 struck Kumamoto, Japan. TSMC is currently confirming the damage situation at its Kumamoto plant.

At 4:27 p.m. on July 28 Japan time, a magnitude 7.1 earthquake struck Kumamoto, Kumamoto Prefecture. Uto City and Hikawa Town recorded the highest Japanese seismic intensity of 7. The Japan Meteorological Agency issued a tsunami advisory for Ariake Sea and Yatsushiro Sea. Kikuyō Town, where TSMC’s JASM wafer fab is located, recorded a seismic intensity of over 5. According to Kyodo News, TSMC is currently confirming the situation at its Kumamoto plant.
(Background: Korean stocks again halted trading, the Nikkei plunged 4%, and Taiwan stocks fell by 1,800 points, losing the 42k level—stock heavyweights went on the run)
(Additional background: Wei Zhejia met with Sanae Takaichi, “Kumamoto covers a 3-nanometer plant,” with investment in Japan surging by $17 billion)

Key highlights

• At 4:27 p.m. on July 28, a magnitude 7.1 earthquake hit Kumamoto; the epicenter depth was 10 kilometers, with a maximum seismic intensity of 7
• Kikuyō Town, where TSMC’s JASM plant is located, recorded seismic intensity of over 5, one step higher than the previous November 2025 event that jumped three levels in a row
• The quake occurred after the close of the Tokyo stock market; market reaction will only be visible after the July 29 opening

At 4:27 p.m. on July 28 Japan time, a magnitude 7.1 earthquake struck the Kumamoto area of Kumamoto Prefecture, with an epicenter depth of about 10 kilometers. The Japan Meteorological Agency observed a seismic intensity of 7 in Uto City and Hikawa Town; a seismic intensity of over 6 in Minami Ward of Kumamoto City, Yatsushiro City, Uto City, Misato Town, and Mashiki Town. It also issued a tsunami advisory for Ariake Sea and Yatsushiro Sea, estimating the maximum wave height at 1 meter. Aftershocks continued, and at 4:39 p.m., Minami Ward of Kumamoto City recorded seismic intensity of 4 again.

TSMC’s JASM wafer fab in Kikuyō Town, Kumamoto Prefecture, recorded seismic intensity of over 5. According to Kyodo News, TSMC is confirming the status of the Kumamoto plant; as of 4:20 p.m. Taiwan time, the company has not yet publicly released inspection results for the site.

On November 25, 2025, a magnitude 5.7 earthquake occurred. At that time, Kikuyō Town recorded seismic intensity of 3. TSMC subsequently said that the maximum seismic intensity measured across JASM’s facilities did not meet evacuation standards.

This time it jumped from 3 to over 5, with three intensity levels in between, so the previous conclusion cannot simply be carried over. When wafer-fab equipment reaches a threshold seismic intensity, it triggers automatic shutdown. Subsequent equipment calibration and wafer rejection inventory checks can easily take hours—what actually happens will depend on TSMC’s official explanation.

500 to 600 people from Taiwan

JASM is a joint venture between TSMC and Sony Semiconductor, Denso, and Toyota Motor. The first plant opened in February 2024 and entered mass production by the end of that year. It provides 40-nanometer, 22/28-nanometer, 12/16-nanometer, and 6/7-nanometer process nodes, mainly targeting automotive, industrial, and consumer electronics. The second plant has already started construction, and combined, the two plants’ planned monthly production capacity is over 100k 12-inch wafers. There are about 2,400 employees at the site, including 500 to 600 people from Taiwan.

The earthquake occurred after the Tokyo stock market closed at 3:00 p.m. on the day. The fastest stock-price reaction from TSMC and its related supply-chain companies will be visible after the market opens on July 29. Japan’s Prime Minister’s Office has set up a response room, and the Chief Cabinet Secretary is scheduled to hold a press conference at 5:30 p.m. local time. In Kyushu, status checks for the Genkai and Sendai core power plants are ongoing; the Ikata Nuclear Power Plant has reported no abnormalities.

Common questions

Did TSMC’s Kumamoto plant get damaged this time?

As of 4:20 p.m. Taiwan time on July 28, TSMC has not yet released inspection results for the JASM plant areas. Kyodo News reports the company is still confirming. What is known is that Kikuyō Town, where the site is located, recorded seismic intensity of over 5, higher than the 3 recorded in the November 2025 event.

What does Japan seismic intensity level 7 mean?

Seismic intensity 7 is the highest tier in Japan Meteorological Agency’s seismic intensity classification. According to the official explanation, in indoor spaces, almost all unsecured furniture will move or fall, and the likelihood of wooden buildings with lower seismic resistance tilting or collapsing increases significantly.