Strong Hawaiian Quake
Sorry about the long absence, but I haven't had much time to post recently. More about that later. Right now, I just thought I'd note the rather impressive earthquake sequence that has started in the last hour in Hawaii. I'll add an update when I know more about the nature of this.
UPDATE: The initially reported magnitudes of 4.6 and 4.9 for the two largest events in this sequence were way too low. They have now been revised to 6.3 and 5.8. It's typical for magnitudes to be revised early on as new information comes in. With that information, this looks like a typical aftershock sequence from a strong shallow quake. The estimated intensity from seismometer data is MMI VI along most of the Kona Coast, with MMI VII near the epicenter. This is enough to cause moderate damage, with the potential for widespread damage near the epicenter. Further updates when any reports of damage or other effects are in.
UPDATE 2: There are reports of landslides blocking Highway 19 along the Kona Coast, and some buildings near the epicenter appear to have sustained structural damage. Power outages are widespread across the Hawaiian islands, including Oahu, so reports are not coming in quickly.
UPDATE 3: The magnitude of the mainshock has been upgraded to 6.6. Mercalli Intensities of VII and VIII have been reported across the entire northern half of the Big Island. No fatalities have yet been reported, but there is extensive infrastructure damage, with many collapsed buildings being reported, and hospitals on the Big Island are reporting numerous minor injuries. Kona Community Hospital was heavily damaged and has been evacuated. Numerous aftershocks are continuing, and affecting the islands of Maui and Lanai as well. The magnitude 5.8 aftershock seven minutes after the quake was likely the largest of the sequence, although there is still a significant risk of further aftershocks of around magnitude 5. A disaster area encompassing the entire state of Hawaii has been declared.
UPDATE: The initially reported magnitudes of 4.6 and 4.9 for the two largest events in this sequence were way too low. They have now been revised to 6.3 and 5.8. It's typical for magnitudes to be revised early on as new information comes in. With that information, this looks like a typical aftershock sequence from a strong shallow quake. The estimated intensity from seismometer data is MMI VI along most of the Kona Coast, with MMI VII near the epicenter. This is enough to cause moderate damage, with the potential for widespread damage near the epicenter. Further updates when any reports of damage or other effects are in.
UPDATE 2: There are reports of landslides blocking Highway 19 along the Kona Coast, and some buildings near the epicenter appear to have sustained structural damage. Power outages are widespread across the Hawaiian islands, including Oahu, so reports are not coming in quickly.
UPDATE 3: The magnitude of the mainshock has been upgraded to 6.6. Mercalli Intensities of VII and VIII have been reported across the entire northern half of the Big Island. No fatalities have yet been reported, but there is extensive infrastructure damage, with many collapsed buildings being reported, and hospitals on the Big Island are reporting numerous minor injuries. Kona Community Hospital was heavily damaged and has been evacuated. Numerous aftershocks are continuing, and affecting the islands of Maui and Lanai as well. The magnitude 5.8 aftershock seven minutes after the quake was likely the largest of the sequence, although there is still a significant risk of further aftershocks of around magnitude 5. A disaster area encompassing the entire state of Hawaii has been declared.
posted by grishnash at 11:10 AM
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