Mapping Earthquake Displacement in Kamchatka: The Power of InSAR
A recent magnitude 8.8 earthquake that struck offshore the Kamchatka Peninsula in eastern Russia highlights the importance of advanced remote sensing techniques. While seismometers provide initial data, a method called interferometric synthetic aperture radar (InSAR) offers a more detailed picture of ground displacement, crucial for understanding fault behavior and forecasting future events.
Understanding Earthquakes and Their Impact
Earth’s surface is dynamic, with tectonic plates constantly interacting. Earthquakes are the result of these plates grinding against each other. Traditionally, scientists have relied on seismometers to measure these events. However, in areas with sparse seismic networks, or when assessing rupture extent, InSAR provides a valuable supplement.
In August 2025, InSAR technology was used to measure ground displacement following the major earthquake that rattled Kamchatka. This technique measures ground displacement—the shifting of the ground away from or toward the satellite—across hundreds of square kilometers by comparing SAR images taken before and after a quake. The image showed that the epicenter did not have the most displacement but an area over 200 kilometers away showed the most displacement.
InSAR: A Detailed Look at Ground Displacement
InSAR, first developed in the 1980s, provides scientists with a precise method for mapping earthquake ruptures, impossible to achieve with seismic networks alone. The image shows ground displacement caused by a powerful earthquake that struck offshore of the peninsula on July 29, 2025. Red areas were pushed primarily eastward by the magnitude 8.8 event. Dashed lines highlight key faults and plate boundaries in the region.
According to Eric Fielding, a geophysicist at NASA’s Jet Propulsion Laboratory (JPL), "Notice how little displacement there was near the epicenter and how the largest displacements were to the southwest more than 200 kilometers away, near the southern tip of the Kamchatka Peninsula.” He further noted that the technique measured an eastward motion of more than 1 meter (3 feet) in the southernmost part of the peninsula.
Practical Applications of Displacement Mapping
Understanding ground displacement has significant practical applications. In conjunction with seismic and global navigation satellite data, U.S. Geological Survey scientists use InSAR data in models that define exactly where and by how much a fault slips, information that is used in tsunami forecasting models. It can also quickly identify the most affected areas after an earthquake, aiding emergency response efforts. Fortunately, in this instance, damage was minimal due to the offshore epicenter and sparsely populated region.
Andrea Donnellan, the head of Purdue University’s Department of Earth, Atmospheric, and Planetary Sciences, highlighted that “This can be used to study how the fault slips after the earthquake, both quietly and via aftershocks.”
Technology Behind the Mapping
The displacement map is based on data from the Advanced Rapid Imaging and Analysis (ARIA) team at JPL, using SAR data from the PALSAR-2 sensor on the Japan Aerospace Exploration Agency’s ALOS-2 (Advanced Land Observing Satellite-2). This technique detects both horizontal and vertical movement, primarily horizontal in this case. Data was acquired on August 2, 2025, compared to a baseline radar image from September 13, 2023.
Detecting Volcanic Activity with InSAR
Beyond earthquakes, ALOS-2 also observed displacement at Krasheninnikova, a volcano that erupted five days after the earthquake. The satellite measured surface displacement, indicating a likely dike of magma approaching the surface. According to Fielding, volcanologists could have recognized the imminent eruption if they had access to this data promptly.
Judith Hubbard, a structural geologist and co-author of Earthquake Insights, stated that “InSAR is one of the main tools that scientists have to understand volcanic activity... Together with other types of data, like gas emissions and seismological signals, it can be used to determine a volcano’s threat level.”
The Future of InSAR: NISAR
While radar data from ALOS-2 has been valuable, the NISAR (NASA-ISRO Synthetic Aperture Radar) satellite, launched in July 2025, promises to revolutionize displacement mapping. Fielding anticipates that “With NISAR, we will get better quality and more frequent displacement maps from earthquakes, volcanoes, landslides, and other processes that cause displacement of Earth’s surface.” He also noted that NISAR’s coverage and L-band radar wavelength will provide displacement maps for heavily forested areas, previously unavailable. NISAR data products are expected within one to two days after observation, enabling faster disaster response.
| Satellite | Agency | Contribution |
|---|---|---|
| ALOS-2 | JAXA | PALSAR-2 sensor for InSAR analysis |
| NISAR | NASA/ISRO | Future improved InSAR data for various Earth processes |
7.4-Magnitude Earthquake Strikes Near Kamchatka (Recent News)
Adding to the region's seismic activity, a 7.4-magnitude earthquake struck near the east coast of Russia’s Kamchatka region on Saturday, according to the U.S. Geological Survey. The epicenter was approximately 69.3 miles east of Petropavlovsk-Kamchatsky, at a depth of 39 kilometers.
Initial reports indicated no immediate injuries or major damages. While the Pacific Tsunami Warning System initially issued a possible tsunami threat, it was later rescinded. This recent event underscores the ongoing seismic vulnerability of the Kamchatka Peninsula, which experienced at least five powerful quakes on July 20 and a magnitude 8.8 earthquake shortly thereafter, triggering tsunami warnings in Japan, the U.S., and Russia.
