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NOAA NCTR research product
Not an official forecast

Kamchatka Tsunami, July 29, 2025
Main Event Page

The July 29, 2025, Kamchatka tsunami was generated by the Mw 8.8 earthquake (52.512°N 160.324°E), at 2025-07-29 23:24:52 (UTC) (according to the USGS). In two days following the mainshock, over 100 aftershocks of Mw 5 or larger were detected, including five aftershocks greater than Mw 6. The 2-day aftershock epicenters occupy a large area of 500 km long and over 150 km wide to the south of the epicenter, which indicate the rupture area of the earthquake.

The analysis sequence for the Kamchatka tsunami was initiated with initial estimates of the earthquake location and magnitude, which understated the actual magnitude of the earthquake by at least a factor of 10—a common phenomenon during initial analysis for large seismic events. The initial forecast based on seismic data gave estimates of tsunami amplitudes at nearby DART systems.

About 35 minutes after the earthquake, tsunami recording of DART 21416 peaked at a maximum amplitude of 0.85 m, the second largest DART amplitude ever recorded. The absolute largest DART amplitude was detected during the March 11, 2011 Japan tsunami (about 1.9 m). The DART record was used to update the tsunami forecast. The tsunami model with the best fit for the DART 21416 used the source with magnitude Mw 8.7. Two more DARTs 21419 and 21415 recorded max amplitudes of 31 cm and 25 cm, respectively, within one hour from the earthquake time. These three DARTs were used to provide the final inversion source for the tsunami forecast for this event at around 1.5 hours after the earthquake. The model tsunami source uses the combination of "unit sources" from the pre-computed generation/propagation forecast database. This final forecast source covered the area of 500km x 150km to the south of the epicenter (Fig. 1).

Map of ocean near Kamchatka with overlays of model tsunami source area graphs
Figure 1. Model tsunami source area (shaded unit sources) based on DART 21416, 21419 and 21415 inversion. Inserts show model comparison at 5 closest DARTs. Click to see large image.

Modeling Results

NOAA NCTR research product NOT an official forecast. The model results are preliminary and produced during the tsunami propagation as a test of forecast capability, not for operational forecast. The tsunami source is estimated from DART data and earthquake information as described.

The forecast of tsunami propagation globally was produced based on the 3-DART inversion (Fig. 2) using the NOAA forecast method with the MOST model.

Map of Pacific Ocean overlaid with tsunami model peak amplitues
Figure 2. Tsunami model peak amplitudes. Click to see large image.

During the tsunami propagation the model showed good comparisons with DARTs further away confirming the accuracy of the propagation forecast model (Fig. 3).

Map of Pacific Ocean with overlays of tsunami model peak amplitudes and DART sea-level records graphs
Figure 3. Tsunami model peak amplitudes and selected DART sea-level records comparing model (red) with data (black). Tsunami model amplitude information is shown color-coded according to the scale bar. Click to see large image.

Propagation Animation

Tsunami propagation map
Click for animation

Preliminary Model Results at Coastal Locations

The global propagation model of the July 29, 2025 Kamchatka tsunami was used to force high-resolution inundation forecast models (a.k.a Stand-by Inundation Models – SIMs) that are available for many tide-gauge locations along the U.S. coastlines. SIM results provide comparisons with tide-gage recordings and estimates of potential flooding zones. Note that while this model output represents the latest research modeling at NCTR, the operational forecast is performed at NOAA's Tsunami Warning Centers (TWCs) using the same technology. The next-generation forecast tools are currently being developed for integration into operations through the Common Analytic System (CAS) project, which aims to unify and modernize TWS operations.

Coastal Sea-level Gauge Comparisons with Model Data

Comparison of the measured tsunami recorded at tide gauges (black) with model results (red) is presented in the graphics below.

Model Inundation Estimates

Model estimates of tsunami inundation at selected Hawaii locations along with model time series at gauge locations (where available) are presented. These are results of high-resolution inundation modeling using propagation simulations as the boundary forcing.

Source:
3.90*ki5a+8.35*ki6z+11.43*ki7a+1.10*ki7b+4.18*ki7z+6.328*ki8a+1.85*ki8b+5.96*ki8z+5.71*ki9a

Disclaimer: The models on these pages show the results of ongoing research to enhance tsunami science and to improve NOAA operational tsunami forecasts. These products were developed during or shortly after the tsunami event, are intended for research use, and are not an official forecast. They should not be used as the basis of any public or private policy decisions. Please contact NCTR to find if there are more detailed follow-on analysis results.

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