Introduction: Mapping Underground Faults and Fractures in Surprise Valley

Tucked in the northeastern corner of California, Surprise Valley is a quiet rural community of about 1,000, set amidst a vast high desert landscape dotted with hot springs and dry lakebeds. But there’s far more going on below the ground than you’d ever know, standing above. From September 1-13, a team of scientists and engineers will collect magnetic data using ground surveys and an aircraft that can fly without a pilot or crew on board, called an unmanned aerial system, or UAS, to map the geophysics below the surface of Surprise Valley.

Why create such a map when hints of the area’s seismic history are plainly displayed on its surface? The corrugated Surprise Valley Fault snakes 85 kilometers along the Warner Mountain Range, the landscape is pocked with smaller surface scars, called fault scarps, that indicate movement along faults, and hot springs billow steam–proof that the area is anything but quiet.

But although some faults and fractures are visible on the surface, some remain completely hidden underground. And even if researchers know where the hot springs are located, they want to understand how hot spring fluids flow through the network of pores and channels underground. Investigating this geothermal fluid circulation system includes identifying faults below the surface that might conduct the hot mixture of fluids and minerals found in the hot springs. These faults also have the potential to rupture during an earthquake, and the detailed studies will help refine predictions of how likely and how damaging earthquakes could be in the region.

Later, the team will compare magnetic data to topographic data they’ve already collected in order to correlate subsurface structures to areas of surface offset, or displacement from the fault center, which indicate active faulting. At the end of the U.S. Geological Survey (USGS)-led, NASA-funded project, which includes a second field session scheduled for next year, they’ll produce a 3-D map that will provide geophysical data on Surprise Valley at a level of detail yet to be achieved for the area. This map will be crucial for predicting the likelihood of earthquakes in Surprise Valley and the damage they may do. The Surprise Valley municipal government can also use the map to inform land and water use decisions, since toxic water zones have been identified in the area, as well to help tap the geothermal system as a sustainable energy source.

The team, which includes scientists and engineers from USGS, NASA-Ames, Central Washington University, and Carnegie Mellon University, will measure magnetic fields using ground surveys and an unmanned aerial system (UAS) to map the geophysics below the surface of Surprise Valley.  Over the years, they’ve collected a wealth of magnetic data by foot and small, four-wheel all-terrain vehicles, or ATV. But the areas they can safely and feasibly survey on the ground are limited. They can’t walk through private lands, dense vegetation, or hot springs, for example. Geoscientists have typically addressed this challenge by contracting pilots to collect data along a specified flight path. Not only are these manned aerial surveys costly, they require pilots to fly at dangerously low altitudes. That’s why the Surprise Valley team will collect data with a small, lightweight, low-flying UAS known as SIERRA (Sensor Integrated Environmental Remote Research Aircraft, photo here). While flying along a preprogrammed path, the NASA-developed SIERRA will relay the data collected by a magnetometer in its wing to a ground station computer. (You can view photos of the team testing the ground base station systems at NASA-Ames Research Center here.) SIERRA is available for other research projects involving the collection of data from inaccessible swaths of land.  Scientists have already employed SIERRA in the NASA-funded Characterization of Arctic Sea Ice Experiment (CASIE) to assess the decline in the ice covering Alaska’s Beaufort Sea.

While SIERRA offers a safer alternative to manned flight, it still has some limitations. With a specified flight path, both manned aerial surveys and UAS run the risk of bypassing interesting geological features. Next year, the Surprise Valley team will collect magnetic data using NASA’s Swift “smart” UAS. The major difference between the two platforms is that an on-board system navigates Swift based on feedback it receives on both magnetic data and environmental conditions, such as wind speed and direction, or obstacles in its path. The system, known as an adaptive payload system, will integrate the magnetic data that Swift’s magnetometer has collected with magnetic datasets into an algorithm that will then “decide” how to adjust Swift’s flight path to maximize data collection in areas of interest.  The team will compare the datasets collected by the two UAS platforms with the goal of developing a cheaper, more effective airborne survey system.

This field season, the team will run additional tests on SIERRA’s ability to correct for magnetic noise associated with the magnetization of the aircraft that would otherwise obscure signals arising from geologic structures we’re interested in. Faults and fractures generate magnetic fields that deviate from those emitted by regions of the valley that lack these features, but so do the aircraft and its maneuvers. SIERRA needs to subtract these readings to ensure that any anomalies that appear in the magnetic data reflect solely features below the surface. 

The researchers will then fly the aircraft in a broad zigzag pattern across Surprise Valley, collecting magnetic data from large features in previously unexplored areas. These data will be important in planning next year’s mission, when Swift will conduct more detailed surveys of the region. The team will concurrently test the payload system by comparing these data against the data collected by Swift.

While airborne magnetic surveys offer complete coverage of an area, there are still reasons to do ground-based surveys. Since a magnetic field weakens with increased distance from the magnetic source, aerial surveys can only detect large fields produced by the gross characteristics of a source below the surface. On the ground, researchers are able to pick up on the more subtle fields produced by a source’s smaller features. During both field sessions, the team will continue to collect magnetic data by foot and ATV (photo) in addition to UAS and will perform gravity measurements along some of the same subsurface structures.  They’ll also drill rock cores to measure remnant magnetization, a record of the magnetic fields at the time the rocks formed, and collect samples from the area to determine density and magnetic susceptibility, which is a measure of how “magnetizable” a rock is. These data will collectively be used to develop gravity and magnetic models to determine the geometry of structures below the surface.

The National Center for Airborne Laser Mapping has already mapped Surprise Valley’s surface features, or topography, using airborne lidar, a highly sensitive technology that can make out even tiny features—visualizing objects and distances as small as a few centimeters. Lidar bounces a laser off the landscape, making a detailed 3-D topographical image. Unlike magnetic field data, which can identify structures below the surface but tells us nothing about their activity, lidar can distinguish active from inactive structures, since only structures that have been active in the recent past produce fault scarps and other areas of surface offset that would still be visible. Otherwise, erosion and sedimentation would have wiped them out. After tying surface offset to subsurface structures, scientists can develop models for the area’s seismic activity.

On this blog, also hosted at NASA’s Mission: Ames and Scientific American’s Expeditions, we’ll share updates on daily missions, glimpses of life in the field, and profiles of individual team members.  We’re excited that you’ll be joining us!

All photos by Melissa Pandika.  You can follow the Surprise Valley team on Twitter @SV_UAS, and view more photos the team in action on their Flickr photostream.

About the Author: Melissa Pandika is a journalism master’s student at Stanford University.  Previously, she studied molecular and cell biology at the University of California, Berkeley and investigated how highly aggressive brain tumors evade therapies that block blood vessel growth at the University of California, San Francisco. You can follow her on Twitter @mmpandika.

I think I began…

Aside

I think I began giving it serious thought last April or May. My boyfriend and I had spent a week in San Diego visiting my sister and his grandparents.  The weather was warm, so we spent it outdoors:  breakfasting on burritos at the beach, meandering through Balboa Park, wandering past art stalls at a street festival, Imagereturning to the beach later at night to watch, hush-quiet, as seals languished in the moonlight, and then to stand giddily near cliff’s edge, listening to the roar of waves without seeing them.So unlike home. Whereas cafes and bars and other “spots” wait around nearly every corner in San Francisco, here they were simple, unassuming.  More like the secret hiding places I used to have when I was younger.

I’ve been itching to return for good.  Of course, the Bay will always hold a special place in my heart, but I’ve been here for twelve years.  I’m growing restless.

Each time bf and I have gone down south to visit, I’ve felt that same tug.  And I’m positive it’s not just nostalgia or post-vacation blues.  I need to get out of here.  I want something different.  Even out in the suburbs, I can’t really shake off that lingering Bay Area feel.  The same cow-dotted hills constantly in view, the midsummer fog rolling in at dusk only a few hours after the sun finally burns through it, the rows of weathered, Victorian-styled houses that always look like they’re sighing.

After so long, even the people, as diverse as they are, have become predictable.  When the BART doors slide open, I can guess who will walk through them with near certainty.  Most likely a drove of fresh-faced suits rushing to work in the FiDi, fingertips gliding over the touchscreens of their shiny Apple devices.  Or, just as likely, a scruffy, flannel-clad Berkeley kid, knees blackened with scabs and bike grease; or a bespectacled, short-coiffed-thirty-something- female, yoga matte and canvas Whole Foods bag in tow.  Oakland Tech students if it’s a Friday afternoon, tousling brass-colored weaves or super long dreads, dressed in fluorescent 80’s throwback get-ups, bumpin hyphy from their cell phones.

Up until recently, I had pretty much abandoned all hope of relocating.  After all, neither bf nor I had anything waiting for us down there.  Nothing secure, at least, no job or grad school admission offers.

Last Thursday, though, bf received an offer from a firm in Milpitas, which also happens to have branches in LA and Oceanside.  Meaning… we may actually be southbound in just a few months!

Ideally, I would secure a reporting position down there.  Realistically, I will end up taking a crappy job at Peet’s or Daphne’s while I find a legitimate journalism job.  And even that may be unlikely, especially now.  At this point, though, I’ve accepted the very distinct possibility of having to eke out an existence down there.

I just want my life to start being mine.  Lately I’ve been watching high school and college friends really beginning their lives — graduating from medical school, traveling the world modeling, penning novels, blogging about volunteer work overseas.

Meanwhile I wonder, when will it be my turn?  When will my life begin?  More and more I’ve realized how much of a privilege, a luxury, it is to be able to set out and do whatever you want, whenever you want.  Given my family’s circumstances, the way my parents raised me, the strong sense of obligation they instilled in me  — doing what I wanted was never even an option.

I thought if I was patient, things would get better. But things haven’t changed; they’ve even worsened in some cases.  I’ll be paying off my parents’ mortgage and various other loans for several more years.  In the meantime, if I hadn’t made the switch to journalism, I would have spent years struggling to be more than mediocre as a scientist.   The stored-up resentment against my family, my house, everything, would grow and grow… and it just wouldn’t be worth it.

I realize that my stay in SoCal may be brief.  In all likelihood, I will end up going to grad school out of state.  But this is something I’ve wanted to do for a while, even if it’s only for a year.  If I do go to school out of state, I’ll most likely work in the area after graduating and won’t return to California for who knows how long.  Or maybe, after living in SoCal, I’ll end up loathing it and flee home to the Bay.  The point is, I need to find out for myself.  In the end, this will be good for me, even if it means simply experiencing the confidence and self-assuredness that comes with pursuing a decision I made solely by myself.

Of course, I’ll still help my family get back on their feet.  But I need to set boundaries, which I’ve always had trouble doing.  I know that in the end, they want me to enjoy the happiness and freedom they couldn’t enjoy in the old country.  But then I have to remember that happiness takes effort.  The coming months will be incredibly stressful, doubt-filled, scary, exhilarating, all at the same time.

Finally I can hear it ticking, my time approaching, time to set everything in motion.  It is time.

Title

Aside

I think I began giving it serious thought last April or May. My boyfriend and I had spent a week in San Diego visiting my sister and his grandparents.  The weather was warm, so we spent it outdoors:  breakfasting on burritos at the beach, meandering through Balboa Park, wandering past art stalls at a street festival, returning to the beach later at night to watch, hush-quiet, as seals languished in the moonlight, and then to stand giddily near cliff’s edge, listening to the roar of waves without seeing them.

So unlike home. Whereas cafes and bars and other “spots” wait around nearly every corner in San Francisco, here they were simple, unassuming.  More like the secret hiding places I used to have when I was younger.

I’ve been itching to return for good.  Of course, the Bay will always hold a special place in my heart, but I’ve been here for twelve years.  I’m growing restless.

Each time bf and I have gone down south to visit, I’ve felt that same tug.  And I’m positive it’s not just nostalgia or post-vacation blues.  I need to get out of here.  I want something different.  Even out in the suburbs, I can’t really shake off that lingering Bay Area feel.  The same cow-dotted hills constantly in view, the midsummer fog rolling in at dusk only a few hours after the sun finally burns through it, the rows of weathered, Victorian-styled houses that always look like they’re sighing.

Image

Uncle Don and Auntie Piam lorem ipsum lorem ipsum lorem ipsum lorem ipsum

After so long, even the people, as diverse as they are, have become predictable.  When the BART doors slide open, I can guess who will walk through them with near certainty.  Most likely a drove of fresh-faced suits rushing to work in the FiDi, fingertips gliding over the touchscreens of their shiny Apple devices.  Or, just as likely, a scruffy, flannel-clad Berkeley kid, knees blackened with scabs and bike grease; or a bespectacled, short-coiffed-thirty-something- female, yoga matte and canvas Whole Foods bag in tow.  Oakland Tech students if it’s a Friday afternoon, tousling brass-colored weaves or super long dreads, dressed in fluorescent 80’s throwback get-ups, bumpin hyphy from their cell phones.

Up until recently, I had pretty much abandoned all hope of relocating.  After all, neither bf nor I had anything waiting for us down there.  Nothing secure, at least, no job or grad school admission offers.

Last Thursday, though, bf received an offer from a firm in Milpitas, which also happens to have branches in LA and Oceanside.  Meaning… we may actually be southbound in just a few months!

Ideally, I would secure a reporting position down there.  Realistically, I will end up taking a crappy job at Peet’s or Daphne’s while I find a legitimate journalism job.  And even that may be unlikely, especially now.  At this point, though, I’ve accepted the very distinct possibility of having to eke out an existence down there.

I just want my life to start being mine.  Lately I’ve been watching high school and college friends really beginning their lives — graduating from medical school, traveling the world modeling, penning novels, blogging about volunteer work overseas.

Meanwhile I wonder, when will it be my turn?  When will my life begin?  More and more I’ve realized how much of a privilege, a luxury, it is to be able to set out and do whatever you want, whenever you want.  Given my family’s circumstances, the way my parents raised me, the strong sense of obligation they instilled in me  — doing what I wanted was never even an option.

I thought if I was patient, things would get better. But things haven’t changed; they’ve even worsened in some cases.  I’ll be paying off my parents’ mortgage and various other loans for several more years.  In the meantime, if I hadn’t made the switch to journalism, I would have spent years struggling to be more than mediocre as a scientist.   The stored-up resentment against my family, my house, everything, would grow and grow… and it just wouldn’t be worth it.

I realize that my stay in SoCal may be brief.  In all likelihood, I will end up going to grad school out of state.  But this is something I’ve wanted to do for a while, even if it’s only for a year.  If I do go to school out of state, I’ll most likely work in the area after graduating and won’t return to California for who knows how long.  Or maybe, after living in SoCal, I’ll end up loathing it and flee home to the Bay.  The point is, I need to find out for myself.  In the end, this will be good for me, even if it means simply experiencing the confidence and self-assuredness that comes with pursuing a decision I made solely by myself.

Of course, I’ll still help my family get back on their feet.  But I need to set boundaries, which I’ve always had trouble doing.  I know that in the end, they want me to enjoy the happiness and freedom they couldn’t enjoy in the old country.  But then I have to remember that happiness takes effort.  The coming months will be incredibly stressful, doubt-filled, scary, exhilarating, all at the same time.

Finally I can hear it ticking, my time approaching, time to set everything in motion.  It is time.