by D. Middleton, May 15, 2020 in WUWT
And it’s not Mauna Loa…
UH researchers reveal largest and hottest shield volcano on Earth
Posted on May 13, 2020 by Marcie Grabowski
In a recently published study, researchers from the University of Hawai‘i at Mānoa School of Ocean and Earth Science and Technology revealed the largest and hottest shield volcano on Earth. A team of volcanologists and ocean explorers used several lines of evidence to determine Pūhāhonu, a volcano within the Papahānaumokuākea Marine National Monument, now holds this distinction.
Geoscientists and the public have long thought Mauna Loa, a culturally-significant and active shield volcano on the Big Island of Hawai‘i, was the largest volcano in the world. However, after surveying the ocean floor along the mostly submarine Hawaiian leeward volcano chain, chemically analyzing rocks in the UH Mānoa rock collection, and modeling the results of these studies, the research team came to a new conclusion. Pūhāhonu, meaning ‘turtle rising for breath’ in Hawaiian, is nearly twice as big as Mauna Loa.
“It has been proposed that hotspots that produce volcano chains like Hawai‘i undergo progressive cooling over 1-2 million years and then die,” said Michael Garcia, lead author of the study and retired professor of Earth Sciences at SOEST. “However, we have learned from this study that hotspots can undergo pulses of melt production. A small pulse created the Midway cluster of now extinct volcanoes and another, much bigger one created Pūhāhonu. This will rewrite the textbooks on how mantle plumes work.”
University of Hawai‘i at Mānoa School of Ocean and Earth Science and Technology
by RP Ortega, April 22, 2020 in ScienceAAAS
In May 2018, Hawaii’s Kilauea volcano let loose its largest eruption in 200 years, spewing plumes of ash high into the air, and covering hundreds of homes in lava. The eruption terrified local residents, but it gave scientists a once-in-a-lifetime opportunity to study the volcano’s explosive behavior. Now, a new study claims that extreme rainfall boosted underground pressures and was the “dominant factor” in triggering the eruption.
It’s not the first time rainfall has been linked to volcanic activity, says Jenni Barclay, a volcanologist at the University of East Anglia who was not involved in the new work. Previous research suggests storms passing over Mount St. Helens may have played a role in explosive activity between 1989 and 1991. And intense rains fell shortly before and during the activity of Montserrat’s Soufrière Hills volcano from 2001 to 2003. Rain may have also triggered eruptions of Réunion’s Piton de la Fournaise volcano. Still, Barclay believes rain is, at best, a contributing factor to volcanic eruptions and not the main driver. “It’s a series of coincident events that have led to the triggering of this larger episode,” she says.
Researchers on the new study used satellite data from NASA and Japan’s space agency to estimate rainfall during the first months of 2018, before the start of the eruption. More than 2.25 meters of rain fell on the volcano in the first months of 2018, the researchers found. They created a model to show how the accumulated rainfall could seep into the pore spaces in rocks deep underground, boosting pressures that eventually caused fissures in the volcano’s flank to open up and release magma. When they looked at records of previous Kilauea eruptions going back to 1790, they found that 35—more than half—started during the nearly 6-month rainy season.
by Aylin Woodward, April 25, 201 in WUWT
In May 2017, high tides engulfed parts of the iconic Waikiki beach, edging dangerously close to waterfront hotels. This kind of high-tide flooding, often called a king tide or sunny-day flood, occurs when ocean water surges to higher levels than coastal infrastructure was designed to accommodate. In that case, water levels rose 2.5 feet above average in Waikiki, drowning nearby roads and sidewalks.
According to a 2017 report (which was updated in September 2018), Hawaii’s state capital and Waikiki Beach – along with other coastal strips on Hawaii’s five islands – are expected to experience frequent flooding within 15 to 20 years.
“This flooding will threaten $5 billion of taxable real estate; flood nearly 30 miles of roadway; and impact pedestrians, commercial and recreation activities, tourism, transportation, and infrastructure,” Shellie Habel, lead author of the 2017 study, said in a release.
Now, Hawaii state lawmakers are taking steps to shore up the state’s beaches and coastal cities. A new bill that mandates a statewide shore protection program has passed both houses of Hawaii’s state legislature, and will soon makes its way to the governor’s desk for approval.
All well and good that they want to improve beach resilience. But, the claim that ” Hawaii’s iconic Waikiki Beach could be engulfed by the ocean in 20 years ” is totally bogus.
Here is why: