Images

Overview map and location of the Tracy Arm landslide-generated tsunami event. The imagery is not current, and the South Sawyer Glacier has retreated over a kilometer from what is depicted. 

Oblique aerial photo of the August 10, 2025 landslide captured during a field reconnaissance overflight on August 13, 2025. Look direction is to the west.​

Oblique aerial photo of the August 10, 2025 landslide source area captured during a field reconnaissance overflight on August 13, 2025. Look direction is approximately north.​

Photo of tsunami-inundated shoreline at Williams Cove, near the mouth of Tracy Arm. Look direction is approximately north.​

Oblique aerial photo of the August 10, 2025 landslide taken from across the fiord during a field reconnaissance overflight on August 13, 2025. Look direction is approximately north.​

Oblique aerial photo of the August 10, 2025 landslide source area captured during a field reconnaissance overflight on August 13, 2025. Look direction is approximately north.​

Comparison of (a) pre- and (b) post-event satellite images showing the source area of the August 10th landslide that impacted Tracy Arm. The dashed line in (a) shows the approximate location of the front of South Sawyer Glacier on August 7th, 2025 (mapped from imagery © 2025 Planet Labs PBC).

Oblique aerial photo of the August 10, 2025 landslide, and tsunami trimline, captured during a field reconnaissance overflight on August 13, 2025. Look direction is to the northwest.​

Oblique aerial photo of the August 10, 2025 landslide headscarp. Look direction is to the northwest.​

Oblique aerial photo of the August 10, 2025 landslide across-fiord runup zone and South Sawyer Glacier captured during a field reconnaissance overflight on August 13, 2025. Look direction is to the southeast.​

Oblique aerial photo of the August 10, 2025 landslide and South Sawyer Glacier captured during a field reconnaissance overflight on August 13, 2025. Look direction is to the southeast.​

Oblique aerial photo of the August 10, 2025 landslide. Look direction is to the south.​

Oblique aerial photo of Sawyer Island captured during a field reconnaissance overflight on August 13, 2025. Look direction is to the southeast.​

Map of the United States and its territories showing 2024 International Building Code Seismic Design Categories and Risk Categories.

Map of the United States and its territories showing the distribution of average annualized earthquake losses by region (modified from Jaiswal and others, 2023). Economic losses from earthquakes in these nine regions are estimated to average \$14.7 billion dollars per year.

Aftershock Forecast Sequence-Specific Model Parameters equation 

The probability distribution for the number of aftershocks, P(N), and the forecast can then be computed using the same procedures as for the generic model, using P_seq-spec(a) instead of P_generic(a).

An example of Bayesian updating of productivity parameter (a-value) for the 2010 Mw 8.8 Maule, Chile, earthquake. Immediately following the earthquake, the SZ-GENERIC region-specific a-value distribution can be used.

Screenshot of the Aftershock Forecast for an earthquake in California, showing the information box at the top of the forecast and the four tabs of forecast information.

Screenshot of the Aftershock Forecast for an earthquake in California, with the “Summary” tab selected, and “M4+” and “Show All” selections for magnitude and forecast duration.
 

Screenshot of the Aftershock Forecast for an earthquake in California, with the “Summary” tab selected, and “M4+” and “Show All” selections for magnitude and forecast duration.

Screenshot of the Aftershock Forecast for an earthquake in California, with the “Forecast Table” tab selected.