Large 4.7 Earthquake Big Island Hawaii, Right On the Hilina Slump

stock here: at some point there will be a slump slip of size, and a large Tsunami. Chatty helps below. I am not sure why “scientists” always seem to downplay risks, and then when it happens “we never could have predicted this”. Perhaps they are trying to increase their credibility by appearing to be “the cooler head”. Not cool at all.

The Hilina Slump on the Big Island of Hawaii is a large section of the southeastern flank of the Kilauea volcano that is slowly moving seaward. The potential for significant movement of this slump is a source of concern because it could lead to large earthquakes and possibly tsunamis. Here’s a summary of the geological events associated with the Hilina Slump and related earthquakes and tsunamis over the past 300 years:

The Hilina Slump:
Location: The Hilina Slump is located on the southeastern coast of the Big Island, part of the Kilauea volcano’s flank. It is one of the most significant examples of a volcanic flank slump—a large mass of land that is slowly sliding into the ocean.

Size: The slump covers an area of over 5,000 square kilometers, extending both on land and under the sea.

Movement: The Hilina Slump is moving seaward at a slow rate of a few centimeters per year due to volcanic activity and gravity. The area is regularly monitored for signs of accelerated movement, which could indicate instability and the potential for a large landslide.
Earthquakes Associated with the Hilina Slump:
1868 Earthquake: One of the most significant seismic events associated with the Hilina Slump occurred on April 2, 1868. This was a massive earthquake estimated at a magnitude of 7.9, which struck the southeast coast of the Big Island.
Damage: The earthquake caused widespread destruction, including the collapse of buildings and landslides. It also triggered a major tsunami.
Tsunami: The tsunami generated by the 1868 earthquake devastated coastal areas, with wave heights reported to be as much as 15 meters (50 feet) in some locations. The tsunami reached as far as California and Japan, though with less intensity.
1975 Kalapana Earthquake: On November 29, 1975, a magnitude 7.7 earthquake struck near Kalapana, on the southeastern flank of Kilauea. This earthquake was also associated with the movement of the Hilina Slump.
Tsunami: The quake generated a tsunami with wave heights of up to 14 meters (46 feet) locally. It caused extensive damage along the Hawaiian coastlines and resulted in two fatalities.
Slump Movement: The 1975 earthquake caused a significant shift in the Hilina Slump, moving the coastline seaward by up to 8 meters (26 feet) in some areas. This event heightened concerns about the potential for larger, more catastrophic movements.
Tsunami Potential and Concerns:
Tsunami Risk: The movement of the Hilina Slump, especially in the event of a rapid, large-scale landslide, could generate a massive local tsunami that would devastate the Hawaiian Islands and possibly affect distant coastlines across the Pacific.
Modeling: Scientists have modeled worst-case scenarios, where a sudden collapse of the Hilina Slump could result in extremely large tsunamis. Some models predict wave heights of up to 30 meters (100 feet) or more in extreme cases, though such scenarios are considered rare and unlikely in the short term.
Recent Activity:
Slow Slip: In recent years, the Hilina Slump has continued its gradual seaward movement, but there have been no significant events comparable to the 1868 or 1975 earthquakes. However, Kilauea’s frequent eruptions and seismic activity in the area keep the region under close observation.
2018 Eruption and Seismic Activity: The 2018 eruption of Kilauea triggered increased seismic activity in the region, with thousands of small earthquakes. While this did not cause a large slump collapse, it served as a reminder of the area’s potential instability.
Conclusion:
The Hilina Slump is a geologically active and potentially dangerous feature of the Big Island. While the slow movement of the slump is normal, past earthquakes associated with it—such as those in 1868 and 1975—have caused large tsunamis and significant damage. The potential for future large-scale movement and resulting tsunamis is a subject of ongoing research and monitoring, as even a partial collapse of the slump could have devastating effects on the Hawaiian Islands and beyond.