Safe Human Settlement Policy Initiative

Safe Human Settlement Policy Initiative

Thursday, May 10, 2018

Pele's Wrath

The island of Hawaiʻi, the largest of the chain that comprises our 50th state, is built from five separate shield volcanoes that erupted somewhat sequentially, one overlapping the other. [Wikipedia] 

The diagram (from another Wikipedia page) shows the United States Geological Survey hazard mapping for the island.  The lowest numbers correspond with the highest hazard levels.  The various volcanoes that comprise the island are shown below, listed below from oldest to youngest:


·       Kohala – dormant
·       Mauna Kea – dormant
·       Hualālai – active
·       Mauna Loa – active, partly within Hawaiʻi Volcanoes National Park
·       Kīlauea – active: has been erupting continuously since 1983; part of Hawaiʻi Volcanoes National Park

Earlier this month, a strong earthquake on the island was followed by increased eruptive activity from Kilauea.  To-date, dozens of homes have been destroyed and Hawaii Civil Defense have reported 2,000 people evacuated from their homes, away from the path of the flowing lava.  Hollywood-like scenes of devastation have dominated the nightly news, including images of people fleeing the irresistible rivers of fiery lava while making their way through steaming cracks that opened in neighborhood lawns and roadways.   

Officials warn of explosive eruptions of steam that would lift stone projectiles and ash into the air, should the lava reach subterranean aquifers. They stress that nobody can predict how long nor how extensive the eruption will be.  For now, they move people as far as possible for the danger as possible, though the relentless earthquakes and the threats of ashfall and acid rain remain.

Mauna Loa, the largest exposed (e.g., above the ocean’s surface) volcano in both mass and volume, has historically been considered the largest volcano on Earth.  It dominates the profile of Hawaii’s “Big Island,” and, although it has erupted in the past, it has been decades since it last showed its awesome power.  In what amounts to a sort of “worst case scenario” in the latest series of events, some scientists fear the increased activity at Kilauea will “awaken the sleeping giant” Mauna Loa and trigger a larger eruption.  Obviously they’re not talking a Mt. St. Helens-like event (St. Helens is a composite volcano, noted for explosive eruptions), but the lava flows from the last (1984) eruption of Mauna Loa came within four miles of Hawai’i’s largest city, Hilo.

"When Pele comes, we just move because she has the right of way." Kaliko Baker
Volcanism was obviously a huge part of the culture of the ancient inhabitants of the Hawaiian islands.  They gave the name “Pele” to the goddess of fire, wind and lightning and credited her (accurately so) with creating the islands on which they lived.  Following the events of the last week, many residents of Hawaii are wondering if perhaps the increased activity at Kilauea is, perhaps, a response by Pele to something they did (or didn’t do).

Somewhat tongue-in-cheek, a 21st Century reporter provided the following background to a news story (also the source of the photo) about the latest eruptive activity. But he found that the people he spoke with take ancient legends very seriously.

Residents near the lava zone on Hawaii’s Big Island having been leaving Ti leaves and flowers in front of their homes and near the cracks on the ground as an offering to the fiery volcano goddess Pele in hopes she will spare them from destruction.

“Scientists and experts have tried to predict what’s going to happen but they’ve been wrong,” resident Shannon Malina told Fox News Tuesday. “We are in (Pele’s) hands now. She’s coming back.”  Malina, who has been living in a Red Cross shelter in Pahoa, was forced to evacuate her home four days ago because of a volcanic eruption spewing bubbling lava and swallowing up residential neighborhoods. She believes it’s the work of Pele, who is coming back to right the wrongs of humanity…

Several people on the island in recent days told Fox News they believe the volcanic instability rocking the Big Island is a warning from Pele…. Even as she wept over the destruction, resident Linda Jones told Fox News, “Madame Pele: I have love and respect.”

So just who is this all-powerful Pele? It depends on who you ask.

Pelehonuamea, or Pele as she is more commonly known, is the goddess of fire, lightning, wind and volcanos. Passionate and moody, legend has it that she lives at the summit on Kilauea. Depending on which version of the story is told, Pele spent her most of her life locked in fierce feuds with family members and was prone to epic jealous outbursts that usually ended with her burning down everything in her path... [Sounds just like what’s happening on Hawai’i now.]

“No one said Pele was nice,” Malina says with a little laugh. “But she’ll protect her children, I know she will.”

The news report includes the following statement from a University of Hawaii language professor named Kaliko Baker. 

“Pele the goddess and the Pele the lava are one in the same.  It’s important to know that Pele is as natural to us, Hawaiians, the aboriginals of this island, as the wind that blows, as the ocean that crashes on the shores, as the lava that flows out of the volcano. It’s our norm and when Pele comes we just move because she’s got the right of way.”

In the case of volcanoes and lava flows, this is exactly the appropriate course of action for any human society.  Impacts from storms and floods can be mitigated.  Earthquake damage can be fixed and sometimes minimized by better design. But when faced with a wall of 2,200 degree liquid rock cascading down a slope toward you, there is no other choice than to “get out of the way.”

The lesson for the residents of Hawaii—a lesson they have learned over centuries of experience living under the threat of volcanic activity—is that human settlements have no business impeding the wrath of Pele.  Planning tools like Lava Flow Hazard Zone maps and other locational restrictions try to limit the impact of volcanic activity on communities in the state, but as we’ve seen in the last week, it’s not perfect.   

Even so, having enough respect for nature—or Pele, if you choose—to inform and modify our activity is critical to human survival. 



Wednesday, April 11, 2018

Resource Update 4/11/18

FEMA has published additional Recovery Advisories related to the rebuilding efforts in Puerto Rico that are applicable to many other communities and regions. The hurricane/flood-proofing ideas are extremely useful tools for designers, contractors and other involved in constructing or reconstructing housing in damage-prone areas. The latest information can be found here.



Thursday, March 22, 2018

Zero is a Good Number

As part of a late winter storm system (named “Toby”) that moved through the Southeast earlier this week, at least 13 tornadoes touched down in Alabama.  Buildings like the one in the photo in one community, Jacksonville AL, were seriously damaged and the repair estimates are in the tens, perhaps hundreds of millions of dollars. In fact, at Jacksonville State University, where the devastation was severe, administrators have opted to close the campus for a number of weeks to clean up and rebuild.

Damage left in the wake of an EF-3 tornado in Jacksonville, AL, March 2018
 But a tweet sent out by the National Weather Service in Birmingham, AL, happily reported that there were miraculously no fatalities. The tweet continued with, “Sweeter words have never been spoken after a significant severe/tornado event. Thank You, Central AL, for staying weather aware & heeding warnings on Monday!”

Therein lies the real lesson for all of us, at least for this particular type of natural hazard: Heeding the warnings and taking shelter saves lives.  Obviously, safety is never guaranteed, but if those in harm’s way listen and get out of the way, their chances for survival are far greater.
 

Friday, February 2, 2018

We should all hug (or at least plant) more trees

An article in PhysicsWorld.com cites the work of Sébastien Guenneau (and others) of the Fresnel Institute in Marseille, France and says that “buildings in the future could be isolated from earthquakes by being placed behind rows of trees.”  Apparently, according to the article:
(Photo from linked article)

“…certain seismic waves, known as Love waves, could be diverted away from the Earth’s surface as they pass through a forest containing trees of a certain height. The forest acts like a metamaterial – an artificial structure usually used to steer electromagnetic radiation around objects.

“Best known for their use as invisibility cloaks, metamaterials are made from large arrays of tiny resonators that manipulate light and other electromagnetic waves in unnatural ways. In recent years, however, the mathematics underlying metamaterials have also been applied to other kinds of radiation, including seismic waves. The idea here is to use arrays of suitably-sized objects either below or above ground – holes or posts of some kind – to divert seismic waves around vulnerable buildings.”

Guenneau says that, in practical application, trees would have to be roughly 10-15 meters tall to resonate with horizontal Love waves.  Protecting a building from the vertical “Rayleigh” waves, however, would require trees some 5 times this tall (that would take decades to mature) making it less practical. That said, scientists say that by using trees to prevent horizontal shaking and conventional techniques to “guard against vertical motion, forests could halve the work of civil engineers.”

Much more research is needed to better understand the behavior of these waves and the potential real world applications.  The science, however, is fascinating.  And the potential benefits are worth continued investigation.  

The bottom line is that mature trees are good.  And worth protecting for a variety of reasons.


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RESOURCE UPDATE
This occurred in September, but I just received notice of it via an e-mail blast from FEMA.  The National Earthquake Hazards Reduction Program (NEHRP) issued a new set of Recommended Simplified Provisions for Seismic Design Category (SDC) B Buildings.  For a look at Category B, see Map here

Not all portions of the country are affected, but the new document should be a helpful reference for all in A and B zones looking to improve resilience in the face of such events.  (I happen to live in a Category B area.)  And of course those in Categories C through E will have much more rigorous requirements.  Here’s the link to the new document. 

The introduction to the report includes this statement:

"For Seismic Design Category (SDC) B, which designates a low seismic hazard region, structural engineers still need to complete a full seismic design process to meet the building code requirements.  Seismic design is necessary because earthquakes are a hazard with long return periods and large uncertainties, and the sudden occurrence of earthquakes in SDC B regions, such as the 2011 Mineral, Virginia earthquake, can cause significant damage or collapse if buildings are not properly designed for seismic resistance.  The recommended simplified seismic design provisions described in this FEMA NEHRP document aim to assist structural designers in meeting building code requirements for ordinary SDC B buildings without wading through the full, complex seismic design process in ASCE/SEI 7.”


Tuesday, January 30, 2018

Waves and Wars: Thoughts on Early Warning Systems

Earlier this month, the State of Hawaii issued a warning to its citizens that a missile attack was imminent, telling them to seek shelter immediately.  Twenty seconds after sirens sounded and cell phone tweeted the warning, it was determined to be a false alarm, but the corrective notice didn’t make it out to most until 38 minutes later.  Panic ensued and now the State (and the Federal Government) are working to determine how something like this could happen and prevent such a false alarm in the future.  (See New York Times article on the issue here, also the source of the photo.)


Public warnings are a critical part of protecting people from the potential impacts of any disaster, whether natural or man-made.  And Hawaii is no stranger to disasters. Or attacks.  And so it’s important that the warning system be effective, timely and most of all, accurate.  Unfortunately, the timely and effective warning last week fell short in the accuracy department.  That’s being changed, they say.

The launch of a missile begins a period of preparation wherein the public can seek shelter. While it may only be a few minutes long, time does provide some options for those in danger.  A more common event in Hawaii (and indeed many coastal regions of the world) is a tsunami warning. Again, an earthquake triggers a warning period and allows the public to prepare. Fortunately, not all warnings result in a tsunami inundating the coast; but people will respond.  When it comes to something like a tsunami (or a missile launch, apparently) no amount of “crying wolf” will dampen public response. And that’s good.

But what about natural events that don’t have a warning period associated with it.  Take, for example, the frequent earthquakes that plague many parts of the world.  Will we ever be able to accurately predict them and warn the populations that might be affected by them?  Does an earthquake (or series of quakes in a short period of time) mean “the big one” is coming?

“It’s true, too, that earthquakes in one place can trigger more far away, over thousands of miles. It may even be true that the worldwide coincidence of major quakes is more than coincidence, that there are global patterns that bring disaster into sync.  But the bigger truth is that scientists still don’t know enough about the fundamental physics of earthquakes to predict with precision and certainty when a seismic event will happen. Earthquakes aren’t entirely random, but for the purpose of day-to-day threat assessment, they may as well be.”  (Source here.)

Plans for public safety and for mitigating the impact of diasters of all types must include the realization that early warning may not be possible for some events, and that simply warning and sheltering vulnerable populations isn’t enough. Governments, schools, businesses and homeowners must do all possible to locate and build cities and settlements in such a way that they are safe places to be, even when a disaster is immediately impacting them.   

When there is no warning, moving to a safer place is not an option.  But making all places safer (or choosing not to build them in the first place) is an option we can choose.


Monday, December 4, 2017

"Once a flood plain, always a flood plain"

An excellent article this weekend in the New York Times offers dramatic photo evidence of Hurricane Harvey’s impact on an upscale Houston neighborhood, along with the story of a resident family that were the victims of a common (and apparently legal) practice by developers who truck in soil to raise building lots just above the designated flood area and, thereby, eliminate their obligation to notify buyers of the potential for flood damage. 


These “wet” and “dry” photos (from the article) of the block are telling.  The occupant, a Mrs. Martinez, recalls in the article that “the home builder had assured her that ‘flooding was not even a possibility…’ They would never have bought here otherwise. Flood insurance, of course, was neither required nor needed.”

Mrs. Martinez recounts that, with Harvey’s “rains outside lashing and the water inside rising, the family and their terrified pet, a one-eyed goldendoodle named Coco, took refuge on the second floor. Later that day, rescue boats came and ferried them to safety.”

The lessons in the article are quite worth a read.

Wednesday, November 29, 2017

Imaging Tool to Map Hazards

A recent article by the Washington (State) Geological Survey demonstrates the uses of Lidar (light detection and ranging) technology to map geological hazards. The article explains the process and illustrates its use with fascinating case studies involving hazards common to the Pacific Northwest:  Landslides and Volcanoes.  The article goes on to describe applications of the technology in locating fault lines, predicting tsunami inundation zones, and tracking the courses of rivers over time to predict flooding impact.  The process can also yield incredible images of sub-surface geology.

Clearly the benefits for applying the technology to hazard identification and mitigation are immeasurable.  Hopefully, it will also become a useful tool in educating and convincing policy makers and the general public to address the hazards in a real way.  Being able to target action and resources to more specific geographical locations will be a significant benefit to endangered communities.

Lidar image of the glaciers on Mt. Rainier. (From the Article)

The online, interactive article is well worth your time to read.