Eroding bluffs stand above the shoreline of Lake Iliamna.
2012 was a busy year for scientists working on issues related to Pebble Mine. I’m one of those scientists. I received my PhD studying tsunamis and learned a bit about earthquakes along the way. Given that PLP hopes to build giant dams that need to stand forever, earthquakes are a fairly important question. Between completing my own geologic fieldwork and critiquing the work of PLP and the EPA, there’s been plenty to keep me busy – so much so that I neglected to post anything on our blog about it all year, despite a number of interesting developments.
Backstory: Is Pebble Mine really safe from earthquakes?
If developed, Pebble Mine would tap the largest gold deposit on the planet, and the copper in that deposit would likely be worth even more than all that gold. Its footprint would sit on the headwaters of some of the world’s greatest salmon rivers. It would leave behind towering tailings dams that would pose catastrophic risk for millennia, long after the boom of the mine has been forgotten.
The mine company’s perspective is simple and hasn’t changed since at least 2006: The threat of earthquakes is low because there are no active faults nearby.
This optimistic view of seismic hazard is based on ignorance. Existing scientific studies tell us almost nothing about faults in the area.
How do you tell if a fault is active?
Faults are deeply penetrating fractures in the Earth’s crust. Faulting results when tectonic motion leads to the buildup of stress and causes the rock to shear. A fault is ‘active’ if that process of building stress is ongoing, and earthquakes are thus likely in the future. This differs from inactive faults, where stress is no longer concentrated and earthquakes no longer occur.
How do geologists assess whether a fault is active? They try to determine whether it has produced earthquakes in the geologically recent past (i.e., the past few hundred thousand years). If so, then stress is likely still building up and will lead to earthquakes in the future.
Even very active faults may only produce an earthquake every few hundred years, and we have only been measuring earthquakes for the last century. Therefore, it’s common to have no direct measurements or observations of earthquakes despite that fault being active. Instead, we must rely on geologic evidence – clues showing that an earthquake has occurred.
I wrote a letter of concern in early 2008 to Alaska’s Department of Natural Resources (DNR) about the uncertainty regarding seismic hazard near Pebble.
More importantly, I’ve tried to do something about that uncertainty – trying to locate and characterize earthquake faults in the area myself. In the years since, I have gone into the field to gather data as often as our meager funding would allow, frequently with my colleague Andrew Mattox. As 2012 dawned, we had a few promising leads.
Seven pages out of 30,800
In February 2012, PLP released a whopping 30,800-page “Environmental Baseline Document” (EBD) that included data and analyses from $120 million in scientific studies in the mine area. This document was meant to describe current conditions in the region around the mine – conditions that would both affect and be affected by mine development.
The seismic hazard analysis was only 7 pages long.
I had had high expectations for this document. In earlier statements, PLP hinted at carefully collected geophysical data that might reveal the location of the Lake Clark Fault, a fault that is of particular interest since it’s large and goes somewhere in the vicinity of the mine. It turned out that not one bit of new data was presented in the chapter’s four pages of text plus three figures.
The analysis also used scientific reasoning that was often bizarre or ridiculous. The rocks near the mine site are too strong for faults to break them? Faults follow glaciers? Both of these assertions can be easily disproven by example.
I lambasted PLP in the press and in a detailed report:
“The seismic hazard assessment presented in Pebble Limited Partnership’s Environmental Baseline Document is flawed. It draws strong, optimistic conclusions from weak evidence, and relies on geologic arguments inconsistent with observed evidence. It misrepresents existing research and fails to use key data sets that PLP has in-hand to inform the analysis. A major fault, the Lake Clark Fault, passes near the Pebble prospect. No published studies establish this fault’s location or seismic activity near the prospect, and the hazard assessment presents no effort to positively determine its location. The hazard assessment fails to consider minor faults or induced seismicity. Without further study, the hazard posed by earthquakes is impossible to determine. “
Hig presenting his critique of the EBD at a scientific conference.
It was satisfying to holler, “Your Science is WEAK!” but it left me wondering why it was so weak.
PLP must either be strategically holding back information, or else it lacks the expertise to do a real seismic hazard assessment. Put crudely: Either PLP is lying, or it’s incompetent.
Is PLP lying?
In February 2011, Northern Dynasty, half-owner of PLP, released a report announcing, “The location of [the Lake Clark] fault has been identified as part of a geophysical survey of the region.”
Between this report (which lacked both data and analysis) and an email conversation I had with Ken Taylor, PLP’s former “VP for the Environment,” it appears that this identification was based on studies that PLP had conducted. Yet, the EBD omits this work, which can hardly be an accident. Why rely on old assumptions about the location of the Lake Clark Fault when your own scientists have located it using geophysical data?
Maybe PLP didn’t like the results of its earlier work, so instead it published a false analysis that told a rosier story.
Is PLP incompetent?
Perhaps the poor quality of PLP’s seismic hazard assessment is unintentional. The bizarre assertions, lack of new scientific studies, and misinterpretation of existing literature are mistakes. Graham Greenaway, the main author of the seismic hazard assessment, isn’t even a geologist, so it’s understandable that he might not see the weaknesses. It’s frustrating to me that PLP has stood by its analysis despite my work to clearly lay out the problems (I’ve shared this with PLP on a number of occasions), but what more can you do?
Isolated chunks of sediment floated in a soup of sand, silt, and water presumably liquefied by shaking.
Tales from the dirt
I suppose one thing I could do is try to figure out what’s going on myself. Andrew and I flew out to Lake Iliamna last June in search of evidence of earthquakes. We aimed to check out a couple of leads: A possible telltale sag in ancient shorelines above the lake suggesting a buried fault, and swirled sediment resulting from liquefaction, a common effect of strong shaking from earthquakes.
We hit a geologist’s jackpot: We found where an ancient peat bog suddenly burst open, a great fountain of liquefied sand pouring out to cover the ground. This sort of dramatic liquefaction is rare, and nearly always occurs during strong earthquakes. Examples of this phenomenon can be seen in eyewitness videos during earthquakes in Japan and Christchurch, NZ.
In combination with evidence that we found of tectonic deformation in the old shorelines, this liquefaction is decent evidence for past earthquakes. For more details, you can read our preliminary report.
Who cares about ‘Science’ anyway?
Having publicized our work, I’d like to think that our job here is done. I have contacted scientists working for PLP and regulatory agencies, and ideally they will follow up on our findings, possibly confirming that the Lake Clark Fault is indeed active. Such a conclusion might warrant expensive changes to tailings dam engineering or abandonment of mine plans and prompt these organizations to inform local communities about risks such as strong shaking and lake tsunamis.
Honestly I don’t really understand how scientific results inform regulatory decisions, but what I’ve seen so far does not make me confident. It’s very easy to fail to find evidence. The mine company has financial incentives to overlook evidence of earthquake risk, just as I have financial motivation beyond merely curiosity to find that evidence – my funding comes from groups opposed to mine development. And regulators, ideally the impartial party here, have tight budgets and a broad mandate, thus little time to focus deeply on a difficult scientific problem like this. Tackling this problem would put government scientists into a political minefield that they may not wish to enter.
This year we’ve seen “the system” attempting to face the scientific challenges presented by the massive scale of Pebble Mine. The EPA, on the invitation of villages in the region, conducted a detailed “Watershed Assessment,” which is still under peer review. PLP criticized the EPA’s effort as premature and misguided, and pushed its own process, the PLP-funded Keystone Center dialogue. This in turn has been criticized for its biased exclusion of non-PLP science, among other things. Though I submitted my own work on seismic hazards, it was not considered even during the panel specifically on this topic. These efforts represent attempts to assemble expert assessments and critique PLP‘s science, but we’re a long way off from seeing concrete results from either. Though I’ve repeatedly pointed out unequivocal flaws in PLP‘s seismic hazard assessment, there was no acknowledgment of these issues as of the Keystone meeting in early October. If you want to see my testimony, you can go here, and skip to 17 minutes, 40 seconds.
So I’m going to stick to it. I have more data analysis, and a paper to write and submit for peer review. And hopefully I’ll have funding to get back into the field this summer.
Often it seems like marketers and politicians control the big issues. But I do believe that objective truth has a small edge in the game. It may not guarantee success, but it’s a nice ally to have. I think science is our best tool to uncover this objective truth.
Sedimentary layers show evidence of liquefaction – perhaps caused by strong earthquake shaking.