A 7.5-magnitude earthquake early in the new year raised parts of Japan by as much as 13 feet

The first day of 2024 brought disaster to parts of Japan. At 4:10 pm Japan Standard Time (7:10 UTC), the land on the Noto Peninsula in northwest Honshu began to shake, and the violent shaking lasted for about 50 seconds. Dozens of strong aftershocks occurred within minutes, hours and days after the 7.5-magnitude mainshock.

The earthquake that occurred on January 1, 2024 was the strongest earthquake to occur in Ishikawa Prefecture since 1885, and the strongest earthquake to occur in mainland Japan since the 2011 Tohoku earthquake. The earthquake was felt in most parts of Honshu, including Tokyo, about 300 kilometers southeast of the epicenter. The earthquake was felt most strongly in the towns of Suzu, Noto, Wajima and Anamizu in the northern part of the Noto Peninsula, close to the epicenter.

Damage to infrastructure sparked fires that burned through the community. Heavy snow that fell after the earthquake complicated emergency response efforts and made it difficult for some communities to receive assistance.

While the first rescuers responded to the disaster from the ground, several teams of scientists tracked the damage using satellites. The image above shows the amount of ground displacement caused by an earthquake - the movement of the surface. The red area is pushed northwest. Scattered dark blue and red areas around the airport, as well as other cleared areas and settlements on the peninsula, are likely false signals caused by the shape of buildings or other features reflecting radar signals.

Eric Fielding, a geophysicist at NASA's Jet Propulsion Laboratory (JPL), said: "In some places on the north coast of the Noto Peninsula, the surface moved upward by as much as 4 meters (13 feet). The uplift was so large because the fault ruptured close to the surface - a depth of about 10 kilometers (6 miles). It happened on a steeply dipping fault, and the south side of the fault moved upward - what we call a thrust earthquake."

Earthquakes occur at different depths. Earthquakes that occur between 0 and 70 kilometers are shallow earthquakes, earthquakes that occur between 70 and 300 kilometers are mid-level earthquakes, and earthquakes that occur between 300 and 700 kilometers are deep earthquakes. Earthquakes that occur at shallow depths like this one tend to be more damaging because the seismic waves they generate have less time to lose energy as they travel from the source to the surface.

The map is based on data from JPL's Advanced Rapid Imaging and Analysis (ARIA) team and the Caltech Seismological Laboratory, which develops state-of-the-art deformation measurements, change detection methods and physical models for hazard science and response. The ARIA team used synthetic aperture radar data and pixel shift tracking technology from the PALSAR-2 sensor on the Japan Aerospace Exploration Agency's ALOS-2 (Advanced Land Observation Satellite-2) to measure surface displacements within the line of sight between the ground and the satellite.

Supplementary analysis of ALOS-2 observations by scientists at the Japan Geospatial Information Agency showed that the earthquake raised land along 85 kilometers (52 miles) of coastline. The coastline of Shuiyue Bay has moved about 200 meters seaward, making it one of the most severely uplifted areas. They also reported substantial uplift and new land at Waijma and Nafune.

Hideaki Goto, a geomorphologist at Hiroshima University, and colleagues from the Japan Association of Geographers used aerial photos and satellite data to estimate that the earthquake exposed a total of 4.4 square kilometers of land along the Noda Peninsula.