We Can Work It Out: Strengthening Societal Resilience to Natural Hazards

Amir AghaKouchak - University of California, Irvine CA
Ben van der Pluijm - University of Michigan, Ann Arbor MI

Flooding from Hurricane Harvey in Port Arthur, Texas (August 2017). 

Photo by U.S. National Guard.

Strengthening societal resilience by focusing on the interactions between natural hazards, the built environment and human societies

The costliest hurricane season in the history of the United States, widespread flooding in South and Southeast Asia, and wildfires and droughts around the world made 2017 the most impacting disaster year so far. Natural hazards are part of our planet’s life cycle, but are increasingly resulting in devastating human disasters (e.g. 2010 Haiti Earthquake; 2004 Indian Ocean Tsunami; 2005 Hurricane Katrina; 2008 Cyclone Nargis; 2011 Tohoku Tsunami; 2017 US hurricanes, 2016-18 California and Canada Wildfires; 2018 global heatwaves), highlighting our vulnerability to extreme events around the world. The key question is: What does it take to prevent natural hazards from becoming human disasters? 

Addressing this question requires a critical look at the societal response to extreme events. A society that experiences frequent earthquakes often responds by improving regulations and building codes to enhance its resilience against future quakes. Over time, even a major natural hazard (e.g., an earthquake) may not lead to a human disaster. A moderate event in an unexpected region or unprepared society, on the other hand, can easily turn into a human disaster without proper preparation. Understanding critical thresholds are fundamental to prevent natural hazards from becoming human disasters, leading to another important question: How can the scientific community inform societies about critical thresholds and strengthen their resilience against natural hazards? 

In the geoscience community, most studies on natural hazards focus on describing and understanding (historical and projected) changes to frequency and intensity of extreme events (e.g., floods, earthquakes, heat waves, droughts, surge, wildfires). However, society’s critical thresholds largely rely on existing infrastructure and our coping capacity. The engineering community has a long tradition of designing infrastructure based on observed historical extremes (considering some safety factors to address variability and uncertainties in historical data), but in many regions the statistics of extremes (mean, frequency, variability) have changed and will continue more so in the future. Thus, any change in the way we prepare our societies and design our built environment would also require support from policy makers. This calls for the three research communities, geoscience, engineering and policy, to focus more on the interactions between natural hazards and the built environment and human societies. In the following, we discuss three areas that warrant attention.

Frameworks for understanding how the interwoven relationship between hazards and the built environment may amplify or suppress likelihood of a human disaster

In February 2017, a series of extreme rainfall events led to failure of the spillway of the Oroville Dam in California, requiring sudden evacuation of nearly 200,000 residents [Vahedifard et al., 2017; Hutton et al., 2018]. A false sense of security follows building major infrastructure systems to protect us against natural hazards; a notion known as the levee effect [Di Baldassarre et al., 2015; Hutton et al., 2018]. The levee effect indicates how lack of (or infrequent) exposure to hazards increases the societal vulnerability to a major human disaster. Given continues developments around the world and changing characteristics of natural hazards, we need more integrated research to develop theoretical and empirical frameworks for modeling and describing this levee effect and its potential to amplify the likelihood of human disasters.

Understanding the cumulative cost/impacts of non-extreme events

Most of the ongoing research on natural hazards focuses on extreme events/disasters with significant impacts. However, recent studies show that low cost and diffuse incidents over time can aggregate into very high cost outcomes [Moftakhari et al., 2017]. While these non-extremes events, such as nuisance flooding, may not lead to human disasters directly, they drain the resources of societies and limits their ability for long-term resilience planning and management. When responding to non-extreme events, acting too soon can waste resources, but acting too late can lead to substantial financial losses. Some of the most critical decisions for policy-makers and stakeholders are when and where to invest in prevention measures, and how to evaluate the financial return. Given observed and projected sea level rise, nuisance flooding has become a paradigm example of frequent minor events with substantial long-term impacts. Unfortunately, our ability to study non-extreme events are limited by lack of data on their impacts/costs, mainly because such events do not receive a great deal of attention. To improve our understanding of non-extreme events and to evaluate when and where to invest in protective measures, we need coordinated research on this topic and more systematic data collection and impact assessment frameworks. 

Compound events

Most natural hazards (e.g., floods, droughts, wildfires, heatwaves) are caused by a combination of interacting and inter-related physical processes across multiple spatio-temporal scales. This combination of hazards, processes and drivers leading to substantial impacts defines a compound event [Zscheischler et al., 2018]. Most of the existing risk assessment frameworks consider one hazard or driver at a time, potentially leading to underestimation of the risk of natural. Furthermore, a combination of multiple non-extreme events can lead to extreme impacts (e.g., a moderate drought and above average temperatures leading to significant reduction in crop yield). In other words, multiple relatively frequent events occurring together can lead to a high impact, low probability outcome. As above, coordinated research and development for understanding the risk of compound events and their impacts are needed. This is particularly fundamental to improving projections of high-impact events in a changing climate (Sadegh et al., 2018).

References

Di Baldassarre G., et al. 2015. Debates—Perspectives on socio‐hydrology: Capturing feedbacks between physical and social processes. Water Resources Research, 51(6), 4770-4781

Hutton, N. S., et al., 2018. The Levee Effect Revisited: Processes and Policies Enabling Development in Yuba County California. Journal of Flood Risk Management, e12469.

Moftakhari H.M., et al., 2017a. Cumulative Hazard: The Case of Nuisance Flooding, Earth's Future, 5 (2), 214-223, doi: 10.1002/2016EF000494.

Sadegh M., et al., 2018. Multi‐Hazard Scenarios for Analysis of Compound Extreme Events, Geophysical Research Letters, doi: 10.1029/2018GL077317.

Vahedifard F., et al., 2017. Lessons from the Oroville Dam, Science, 355 (6330), 1139-1140, doi: 10.1126/science.aan0171.

Zscheischler J., et al., 2018. Future Climate Risk from Compound Events, Nature Climate Change, 8 (6), 469-477, doi: 10.1038/s41558-018-0156-3.

Modified from AGU Ed Vox: We Can Work It Out: Avoiding Disasters.
Follow us on Twitter: Amir AghaKouchak is @AmirAghaKouchak, Ben van der Pluijm is @vdpluijm

The Meghalayan?

I actually posted “WTF is the Meghalayan?" on Twitter (here).  This in response to the IUGS’s announcement that the Holocene Epoch was officially divided into new stages.  The Meghalayan stage, after a location in NE India, being the youngest, so the one we are living in today.  Two thoughts came to my mind quickly: (1) how thin are we slicing geologic time?; and (2) what about the Anthropocene?

(http://www.stratigraphy.org/ICSchart/ChronostratChart2018-07.jpg)

The relevant section is:

As the new chart shows, the Holocene is now sliced into three roughly 4000y stages.  That is short, faster than a geologic eye blink, with subtle boundaries.  Perhaps a little silly.  How small can relevant slices go, I wondered.  Jokingly, I proposed:

Kennedyan 1950-1963; Dallas
Lennonian 1964-1980; Abbey Road
Mandelaian 1981-2013; Robben Island

With time on my hands, I even identified the location of the required Golden Spike for each:

(https://www.google.com/maps/d/u/0/viewer?mid=1uLoblqY_QztpfB5Rvta8vT71xiNJ2W2N&hl=en&ll=12.09908316080252%2C-39.21812990000001&z=3)

More seriously, I wondered about the status of an eventual Anthropocene in the official time chart.  A large working group has been debating this for several years ongoing, seemingly close to deciding on 1950 as the beginning of that time.  I favor the idea to emphasize the growing role of humans in the geologic system; for example, our large resource and land use, environmental change of ocean and atmosphere, etc. However, I'd place the start earlier, as impacting global colonization and industrial revolutions occurred 100s of years earlier and agricultural appropriations 1000s of years earlier.

I doubt agreement on a start will be easy, so instead I propose that we replace Holocene with Anthropocene (the Epoch of human emergence and dominance) and relegate Holocene as a Stage/Age (the last glacial deposits and a warming planet).  The huge changes of the past 150-200 years would be captured by the Modern Age, which is recognizable and already used informally.  My proposal below.

I have little idea what will come of this, but, hopefully, some fresh discussions on the meaning of the geologic time scale and the value of identifying geologic boundaries. The process of decision making is decadal, so I am not holding my breath.  I was surprised, however, that officials made another move.

Deposit of the Modern Age with plastic and aluminum "fossils" (Kobe, Japan).

A nice piece in The Atlantic, “There’s No Collusion”: Geology’s Timekeepers Are Feuding
-- “It’s a bit like Monty Python." offers some background on process and value, and may help this discussion along.  It includes my lighthearted characterization of the process as the "Ministry of Silly Cuts" (maybe not helping things along).  Enjoy this well-written The Atlantic piece and see that geologists are people too, with intrigue and tensions.

(https://www.theatlantic.com/science/archive/2018/07/anthropocene-holocene-geology-drama/565628/)

In the end, the discussion and decisions should revolve around recognizing the changes and challenges facing modern society as we have to rely on Earth for the foreseeable future, and the contributions of geology to our actions in a changing world.

May 2019
Disappointingly, but not unexpected, the Anthropocene Working Group selects 1950 as the start of the Anthropocene.  Baby Boomers rule, but showing little regard for the geologic timescale.  Perhaps a GoT-like redo on change.org with 1.5+M signatures?
See: https://www.nature.com/articles/d41586-019-01641-5

---------------
Follow Ben van der Pluijm on Twitter as @vdpluijm; for example:

Talking Volcanoes and Hazards

Volcanoes in Hawaii, Guatemala: Faculty Q&A

More than 100 people were killed and nearly 200 remain missing after the violent eruption of Guatemala’s Fuego volcano June 3. Meanwhile, lava has destroyed more than 600 homes on Hawaii’s Big Island since early May in the latest eruption of the Kilauea volcano.

University of Michigan geologist Ben van der Pluijm, a professor in the Department of Earth and Environmental Sciences and editor-in-chief of the journal Earth’s Future, examines the impacts of natural hazards on human society. He discussed the two recent volcanic eruptions.

What are the main differences between the Kilauea volcano in Hawaii and the Guatemala’s Fuego volcano?

Hawaii’s volcanoes, like Kilauea, are caused by heat in the Earth’s mantle rising to the surface in a column called a plume. Hawaiian volcanoes mostly produce slow-moving, gooey lava, creating a broad, low-topography structure called a shield volcano. The biggest hazard from these volcanoes is unstoppable magma flow, and the latest Kilauea eruption has already destroyed many hundreds of houses. But because the lava moves slowly and can be outpaced, these events typically cause no loss of life or major injuries.

Explosive volcanoes like Guatemala’s Fuego have a very different origin from Hawaii’s. They are related to plate-boundary tectonic processes that produce a stickier magma in the outer layers of Earth. Greater magma stickiness resists buildup pressure from below until it releases in a sudden, explosive manner. These eruptions are quick and large, and they often produce deadly clouds of hot ash, lava, rock and gas that roll downslope at great speed: a hot pyroclastic flow. This is the primary source of the great loss of life in Guatemala, much like Pompeii from the Vesuvius eruption in the first century.

What can we expect from these two volcanoes in the coming weeks and months?

Kilauea has been erupting for more than a month and may be reaching the end of its current cycle. Another eruption cycle will eventually follow, however, because the driver for magma generation persists, and the volcano has been regularly erupting for decades.

Fuego released most of its energy in the early eruption, so it may become quiet. As elsewhere, however, the volcanism won’t stop. It simply takes a hiatus. Other volcanoes in the region may similarly erupt at some point, since the underlying magma-generating process—melting from convergent plate tectonics—continues unabated.

The voluminous ash and rock deposits that are left behind after a Fuego-style explosion are often unstable on steep mountain slopes, especially when rain wets the material. These deposits can wash downslope as dense, debris-rich, destructive flows known as cold mudflows. These flows can destroy houses and agricultural land, covering the area with mud and rocks.

How common are volcanic eruptions globally?

Worldwide, several dozen volcanoes are erupting at any given time. Several hundred volcanoes around the globe, including more than 160 in the United States, are considered active, meaning that they have erupted in historic time. The Kilauea and Fuego eruptions are therefore not at all unusual or unexpected, except they have greater impacts on nearby human settlements than other active volcanoes around the world.

What technologies are used to forecast volcanic eruptions?

Many volcanoes show seismic activity as pressure builds and magma starts to move around. We measure this seismic signal with local seismometers stationed near and on the volcano. Another gauge of possible eruptive activity is the use of surface tilt meters that measure ground deformation from inflation of the volcano in response to moving magma. Also, remote sensing and satellites are increasingly employed to monitor changes around active volcanoes.

Thus, volcanoes can offer some precursor activity, but uncertainty toward full eruption remains too large for reliable societal prediction, and the warning period before an eruption can be short. Instead, people living near active volcanoes need to be informed and prepared because those volcanoes will, eventually, become active again.

What is the connection between the Kilauea eruption and the earthquakes that have been occurring there for more than a month now?

The generation and movement of magma beneath Kilauea creates pressure changes in the subsurface that generate earthquakes from rock fracturing. And inside Kilauea’s volcanic depression, which is called a caldera, earthquakes occur when magma pressure is released by rock collapse and fracturing, and by venting at the surface.

During its latest eruption, Kilauea has displayed a remarkable pattern of repeated earthquakes of magnitude 5 or greater, equivalent to the explosion of 500 tons of TNT. These events are often associated with ash eruption, following a one- to two-day pressure buildup. This seismic activity will eventually subside.

Ben van der Pluijm posts about geohazards and societal impacts on Twitter as @vdpluijm. A selection of Kilauea Twitter posts are archived at https://vdpluijm.blogspot.com/2018/05/kilauea-2018.html

June 2018; from Michigan News, https://news.umich.edu/volcanoes-in-hawaii-guatemala-u-m-expert-discusses/

Kilauea 2018 eruption

UM News&Information

May 4
Hundreds of small and a few larger earthquakes have occurred in the past week—including a magnitude-5 on May 3—indicating that magma in the Kilauea volcano is on the move. Several surface fissures with magma fountains have already formed, and evacuation planning is under way for thousands of residents.

This type of eruption is less dangerous to human life than stratovolcanoes like Mount St. Helens and Mount Pinatubo, which are characterized by explosive volcanism and large ash clouds that reach into the stratosphere,” van der Pluijm said. “Hawaiian volcanoes are characterized by red-hot magma that bubbles and flows, and minor explosive activity. However, flowing hot lava destroys everything in its path. The Big Island is the most recent expression of millions of years of volcanism along the Hawaiian chain.

May 9

Kilauea has been continuously erupting for more than 35 years. Though this recent activity is a more active episode, it is not otherwise unusual. With about 100 acres covered by new lava flows, this latest Kilauea flare-up produced less than 1 cubic kilometer (about 0.2 cubic mile) of eruptive volume so far, which is a modest amount in the volcano's history. 

More than 1,000 shallow earthquakes reflect recent deep magma movement, fissures and subsurface displacements, including two larger quakes that rocked the area in the past week. These displacements have resulted in about 2 feet of seaward, southeast-directed movement of the volcano's south flank. Potential instability of Kilauea's south flank adds a Pacific tsunami hazard risk if land collapses into the sea.

May 17
Any danger is limited to the easternmost part of the Big Island. These types of eruptions are not that violent, except the potential of occasional steam-driven explosions that throw ash and rocks around in a small area. Better to keep some distance, and evacuate, regardless,” he said.

Fissure eruptions and slowly flowing lava are characteristic for the Big Island geology, with explosivity less common but recorded in prior eruptive events in the area as well. The origin of explosions is not the magma type, but heated water, somewhat analogous to a Yellowstone geyser.

Twitter (@vdpluijm)

May 1
Collapse of crater floor on #Kilauea Volcano’s East Rift Zone prompts increase in #seismic activity.  More lava coming? #Hawaii #volcano #geology

May 4
M6.9 was 7000 km away and my home shook 11 min later (well, my basement seismometer felt it). @raspishake #earthquake

May 9
The other source of explosive volcanism, driven by magma submersion below groundwater table, not (silicic) composition of the magma.  Dangerous as well. 
This diagram shows how explosive eruptions occur at Kilauea: 1) lava column drops below the water table; 2) groundwater comes in contact with magma or hot rocks, 3) the flash boiling of water causes violent steam explosions.

May 12

Nicely illustrated summary of 2018 #Kilauea eruption event thus far, and its impact. More lava (and ash?) may be ahead.  #Resilience #geohazard  -- ‘Shell-Shocked’ in #Hawaii: How Lava Overran a Neighborhood

https://www.nytimes.com/interactive/2018/05/12/us/kilauea-volcano-lava-leilani-estates-hawaii.html 

May 14

The Pacific Tsunami Warning Center created an animation of recent earthquake and volcano activity at Hawaii's Kīlauea Volcano, from April 21 to May 13, 2018. Thousands of small (<M3) and a few larger earthquakes, in addition to multiple fissure eruptions. Kilauea is not likely done, with more honey-like lava (effusive eruption) ahead and perhaps some steam-powered explosivity (phreatic eruption). #hawaii #geohazards -- youtu.be/bm9ezJQBOXs

May 17

May 14 Landsat image of Kilauea eruption region (+ some clouds).  Red marks active vents; recent flows gray; forest green; houses white.  Notice formally bubbling Pu’u ’O’o vent is now drained and a steady plume at Kilauea.

https://earthobservatory.nasa.gov/IOTD/view.php?id=92156

May 24
Lighter touch: The importance of Hawaii lava flows.

June 3
Whereas media coverage of #KilaueaEruption has waned, volcanism has not.  Several M5+ quakes and many smaller mark recent magmatic activity in crater region ("poolball").  

See @NOAA #earthquake animation through May 31: youtu.be/CybGAooIGZY. 

June 7&8

Just like significant tectonic plate boundary earthquakes have recurrence intervals (decades to centuries), so seemingly do volcanic earthquakes.  Kilauea's are 1-2 days leading to M5+. M5 is equivalent to ~500 ton #TNT explosion.

... June's fifth M5+ #earthquake in #Kilauea caldera, like clockwork.  Growing foreshock pattern is distinct from tectonic quakes that are characterized by aftershocks. Depth-magnitude-time plot (from VolcanoDiscovery):

June 11

Is Kilauea the new and bigger "Old Faithful"? Not exactly, but steady daily recurrence of M5+ earthquakes and venting continues.  Persistent absence of M4-5 quakes in caldera is a head scratcher (see plot), but may represent different processes in the volcano. 

July 6

Hawaii's "New Faithful" volcano continues with #earthquakes like clockwork.  On average just over 1 day (~1.2) between explosions in #Kilauea. Surprisingly consistent pressure cycling in its plumbing. 

July 21

Kilauea lava eruption and its future reported by USGS: 

- >430M m3 lava erupted so far is largest in centuries. 

- lava delta extends >800m from pre‐eruption Kapoho Bay coastline. 

- eruption may continue months to years.

https://volcanoes.usgs.gov/vsc/file_mngr/file-185/USGS%20Preliminary%20Analysis_LERZ%20July%2015%202018.pdf

Lava delta. une 18, 2018 (USGS)

August 8

Hawaii's Kilauea volcano hits pause button. Little lava flowing, no explosive earthquakes at caldera. At best, a geologic pause (=yrs, decades), but may also be only a human pause (=days, weeks). Activity will return, so stay alert, BigIslanders. 

Kīlauea's summit is quiet. August 2 (USGS)

August 14

Kilauea update. The geologic pause of lava flow and explosions continues, while coastlines redrawn (pic of new Pohoiki Bay). Flows not yet cold, but bill is, like the #BigIsland, growing: $680M. Cost of predictable #geohazards will be unsustainable.

Pohoiki Bay. August 12 (USGS)