When the Hawaiian Islands collapse and fall apart in landslides

January 28, 2014HAWAII In our January Volcano Watch articles — Hawaii Island’s fifth annual Volcano Awareness Month — we are exploring important questions about how Hawaiian volcanoes work. Last week, we discussed how Hawaiian Islands grow; this week, we talk about how they fall apart. In 1964, irregular submarine topography north of Oahu and Molokai was identified in newly available maps of the sea floor made by the U.S. Navy. James Moore, then Scientist-in-Charge at the USGS Hawaiian Volcano Observatory, suggested that this odd bathymetry might reflect massive landslides originating from those islands. Moore’s interpretation was disputed for more than 20 years until comprehensive mapping of the sea floor around the entire state of Hawaii was completed in the late 1980s. It turned out that Moore was right. Large — even catastrophic — submarine landslide structures litter the sea floor around the Hawaiian Islands. In fact, 17 major landslides have been identified off the shores of the main Hawaiian Islands. Fortunately, these slides are exceedingly rare — occurring, on average, only once every 350,000 years. The largest landslides constitute significant portions of the islands from which they originated. Imagine if 10 percent of one of the islands suddenly collapsed into the ocean. Such an event would displace a huge amount of water and cause a large tsunami.
Deposits of coral and sand have been found approximately 1,000 feet above sea level on several of the Hawaiian Islands. Catastrophic landslides are believed to have generated gigantic tsunami waves that washed ashore and left these deposits behind. Evidence across the Hawaiian Islands suggests that landslides occur during all stages of a volcano’s life. The submarine volcano Loihi — the youngest in the Hawaiian chain, located southeast of Hawaii Island — is characterized by a number of small landslides, even though the volcano hasn’t yet breached the surface of the ocean. On the other hand, large landslides from Oahu and Molokai clearly occurred well after the islands were established above sea level. We also know that not all landslides in Hawaii are catastrophic. The south flank of Kilauea is sliding continuously into the ocean at a rate of about 3 inches a year. This motion is punctuated by large, devastating earthquakes that can cause tens of feet of seaward motion in just a few seconds — as when the magnitude 7.7 temblor struck Hawaii Island in 1975 — as well as “slow earthquakes” that are associated with a few inches of seaward motion over the course of one to two days.
Will Kilauea’s south flank ever collapse suddenly? Since the shape of the south flank indicates that the slide has been active for thousands of years, there is no reason to expect that its behavior will change any time soon. Although most evidence suggests that it will continue to sag gradually, this question remains open to interpretation. What, then, causes large landslides in Hawaii? Models suggest that magma pressure alone is not adequate to produce a massive landslide. One can imagine a scenario, however, in which a large eruption weakens an already unstable volcano, allowing gravity to pull the volcano apart. Future scientific research must focus on the mechanism for giant landslides in Hawaii, which represent a major, infrequent hazard. Since other volcanic islands — such as the Canaries and the Azores — are also subject to catastrophic collapse, lessons learned from the Hawaii example might be fruitfully applied to mitigating hazards for the benefit of citizens elsewhere around the world. Next week, our annual Volcano Awareness Month Volcano Watch series will conclude with an examination of questions related to volcano monitoring.  –WHT
This entry was posted in Civilizations unraveling, Earth Changes, Earth Watch, Earth's core dynamics, Earthquake Omens?, High-risk potential hazard zone, Land fissures, cracks, sinkholes, Landslide & geological deformation, Lithosphere collapse & fisssure, Magma Plume activity, New land rises from sea, Potential Earthchange hotspot, Seismic tremors, Signs of Magnetic Field weakening, Strange high tides & freak waves, Tectonic plate movement, Time - Event Acceleration, Volcano unrest, Volcano Watch. Bookmark the permalink.

7 Responses to When the Hawaiian Islands collapse and fall apart in landslides

  1. Jim says:

    How often have these landslides have hit western United States cost line?


  2. Barbara Wong (BJW) says:

    I had three repeated visions of tsunamis, 80 to 90 feet in height, traveling through the the highrise buildings in down-town Honolulu, our capital, reaching up to the H-1 freeway. I do not know the date of when it will occur. Wilbert W. W. Wong, Sr.


  3. Larz says:

    I suggest you look at the 1957 Lituya Bay Alaska Tsunami caused by an earthquake and landslide. It can happen anywhere. Earth is in the mid-way point of a 32 year Volcanism. The flank collapse is near! Couls be El Hierro or La Palma, from deep in the Atlantic, Iceland, Cascadia, any one of the Hawaiian islands, Alaska coast, Carribean, yes, you guessed it, many many areas. Question of just when. Soon geological time. In the next few years…unfortunately. Even CA coasts have the San Andreas that cloud cause a massive landslide. It is close, very close. I sense it. I hope I’m wrong because the damage and loss of life would be unpresidented in human history!


  4. tony says:




  5. Jeff says:

    Surprised the kitchen cabinet door fell off several times that repeated tightening the hinge screws and it was never used not opened for purpose …Well turned out the power line to the corner of my two story roof vibrated and like a drum or vibration test magnifying and focusing at the opposing corner ten yards diagonal …..Well I awaken before dawn like every chance to be at my sacred moment hours before dawn as in Dawn Patrol coffee in hand outside on the road stargazing alone go over the stars etc and the once wonder of it all,rehearsing peak experiences and seeing my purpose and such wide awake anticipating the dawn as a miracle of animation processes of this one point in time where this is the only LIFE anywhere and my role so the telephone pole thirty feet tall anchored by three enough rigid steel cables holding the TOP START SHAKING WILDLY 12-16″” roaring sounds then the sun already rises for minutes the shaking tapers off and another cup of fresh brewed instant longs sale item .So I figure it out and await the Aliens


  6. Jeff says:

    The Mayan calendar was uncanny once the source of the muons was associated so big cheers ancients pyramids globally There is some smarts out there but where and when such a deception ?humm Sherlock enjoys this sheet


  7. Matheus says:

    According documentaries, if the whole side “Hilina” fall into the ocean, a gigantic tsunami is generated, advancing and destroying Honolulu more than 16 km inland, and would move in the direction of Los Angeles on the west coast of the United States and may cause major damage.


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