Julie Elliott
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julieelliott.bsky.social
Julie Elliott
@julieelliott.bsky.social
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Research Faculty at Michigan State University. Geodesy, Tectonics, and Glaciers. All opinions my own.
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julieelliott.bsky.social
Cool study that uses acoustic signals recorded at seismic sensors to identify aircraft type flying overhead (different aircraft have different frequency signatures). Alaska provides a lot of aircraft variety to evaluate. ⚒️🧪🚁

pubs.geoscienceworld.org/ssa/tsr/arti...
a. Seismogram from one of the seismic sensors (largest signal is an earthquake). b. Residual spectrogram (difference between the spectrogram and the amplitude spectrum (red line at left). Curves overlain with dashed lines are the aircraft signal. The broad/smeared signal at lower frequencies is from an earthquake. c. Aircraft that made the signal, a Cessna 185. d. Flight pattern for the aircraft (blue) and locations of seismic sensors (red). Cross section of the residual spectrum along dashed line in b, large signal near beginning is from an earthquake.
November 20, 2025 at 5:58 PM
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#30DayMapChallenge Day 4: My Data

Hardware stores I have visited/spent too much money in while doing fieldwork in southern and interior Alaska. Maybe one day I'll make it through a trip without needing to stop at a hardware store (but probably not).
Topography (and bathymetry) map of southern and interior Alaska along with a bit of the Gulf of Alaska. Turquoise wrenches mark locations of hardware stores scattered throughout the region. Two are off of the road system, so all products have to be brought in via plane or boat. Visits to those stores were particularly expensive.
November 5, 2025 at 5:00 AM
julieelliott.bsky.social
#30DayMapChallenge Day 2: Lines

Think your commute is rough? Here are migration paths of Arctic terns that breed in Alaska. Each color represents the round trip track for an individual tagged bird. Migration data source in comment. Map made with the Generic Mapping Tools (GMT).
Map of the world centered on the western Pacific. Continents/islands are gray while water is pale blue. Various shades of blue and green lines stretch from Alaska, eastern Russia, and the Bering Sea down the western Pacific margin to Antarctica. The lines are very much not straight, but weave around and sometimes double back.
November 2, 2025 at 9:16 PM
julieelliott.bsky.social
Today is International GNSS Day. October 23 was chosen because 10.23 MHz is the foundational frequency for GPS. The world has become dependent on GNSS, but there are threats to service continuity. It is good to take a day to appreciate the value of GNSS. #geodesy www.ion.org/news/interna...
Banner with dark blue background with ION (which stands for Institute of Navigation) logo in upper right and International GNSS Day 2025 10.23 below. A white banner saying Celebrating 30 Years of Galileo is in the lower right corner. On the left, a man representing Galileo the scientist has a hand raised toward a GNSS satellite surrounding by a circle of starts.
October 24, 2025 at 1:46 AM
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For #FieldworkFriday, some of the benchmarks I've surveyed over the past few weeks. Some are more challenging to use than others, but they're all interesting. #geodesy ⚒️🧪
Brass disk with a circle in the center. Inside the circle is a line with a punchmark/divot in the center. In concentric circles around the center circle are inscriptions: "4240T 2000 For Info Contact Director Washington DC National Ocean Service Bench Mark". Brass disk recessed into paving. A layer of mud and moss had to be removed to find it. There is a circle in the center of the disk with two lines dividing the circle into quarters. Around the outer edge of the benchmark are the words "Z22A 1994 National Ocean Service". A brass disk sites in rock. In the middle of the disk is a triangle with a center divot. At the top of the Triangle, it says TSINA EASTBASE. At the bottom, it gives the year as 1941. Around the edge of the benchmark are the words U.S. Coast & Geodetic Survey Triangulation Station.
October 4, 2025 at 12:29 AM
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A campaign GNSS site in Willow, Alaska, set up to tie previous time series with the new EarthScope/NOTA continuous GNSS site nearby (the old NOTA site got whacked by a snow plow). The white crags in the center background are Mt. Foraker (left), Mt. Hunter (middle right), and Denali (far right). ⚒️🧪
A yellow tripod is set up over a recessed benchmark (that had to be dug out of mud and moss). A white GNSS antenna sites on the tripod. A yellow case sites next to the tripod and holds a GNSS receiver. A battery sits next to the case and is connected to the receiver. Orange cones with reflective strips stand at each tripod leg because the site is at an airport and needs to be visible. A gravel and concrete air strip edged with trees stretches into the background. In the far center background, three large snow covered peaks show above the horizon. the sky is blue with only a few puffy clouds.
October 2, 2025 at 2:31 AM
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Engaged in a bit of gardening this morning. In related news, I'm pretty sure I know why data from this GNSS site has been showing high levels of noise. Also, I hate cottonwood, alder, and their ilk. ⚒️🧪
A stainless steel GNSS antenna monument with three angled legs and one vertical center leg stands in the middle of the photo. A gray radome (with a GNSS antenna inside) is at the top of the monument. Nasty, nasty alder, cottonwood, and other plants have grown very tall around the monument, intertwining their evil branches with the monument legs and interfering with GNSS satellite signals reaching the antenna properly. A stainless steel GNSS antenna monument with three angled legs and one vertical center leg stands in the middle of the photo. A gray radome (with a GNSS antenna inside) is at the top of the monument. You can see the monument now as the nasty vegetation has been broken down and stripped back. The vegetation in the around surrounding the monument has also been broken off and stamped down, so the antenna should be able to receive better signals.
October 1, 2025 at 9:55 PM
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It might seem odd to set up a campaign GNSS site next to a continuous GNSS station, but running both at the same time allows the continuous time series to be tied to the longer campaign times series. Long time series rule! ⚒️🧪
A grassy field is edged with orange and gold trees with a blue sky overhead. Mountains peak out of clouds behind the trees. On the left side of a field, a welded GNSS antenna monument with a gray radome (with antenna inside) stands near a solar panel array with two gray boxes holding electronics and batteries. On the right side of the field, a yellow tripod set up over a campaign benchmark holds up a white GNSS antenna. A yellow box with a receiver and a battery sits near the base of one of the tripod legs.
October 1, 2025 at 3:17 PM
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Some last photos from a GNSS field campaign done a couple of weeks ago before I head up to Alaska again for one more survey before snow sets in. There is bedrock under the benchmark - it was a very good moss season this summer. This site is near Thompson Pass in the Chugach. #FieldworkFriday 🧪⚒️
A round brass benchmark with "US Coast and Geodetic Survey" around the edge in bedrock covered with green moss. A metal spike mount (two adjustable arms holding a spike which sits onto of a benchmark) holds a white GNSS antenna. The site is on a mossy outcrop of rock surrounding by trees, some of which are starting to turn yellow. Worthington glacier near Thompson Pass, Alaska splits into two branches as it goes to lower elevations. It has lost a lot of ice in recent decades. The slopes around the glacier are green and gold. A road curves through trees and tundra in the foreground.
September 26, 2025 at 9:22 AM
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A permanent/continuously operating GNSS site in the Wrangells with fresh batteries and solar panels operating at full capacity (had to do some pruning). Hopefully it is now ready to collect data without interruption over the winter. ⚒️🧪
Trees in shades of gold, orange, light green, and dark green edge a field. In the field, there is a GNSS antenna monument (steel pile driven pipe, about 5 feet tall) with a gray dome on top. This radome protects the GNSS antenna underneath. A long cable runs from the antenna to a gray plastic box (only a corner is visible). The box contains batteries, electronics, and a GNSS receiver. Next to the box, two solar panels are attached to a steel pole. The sun is reflecting strongly off of the solar panels and some recently pruned vegetation is around the bottom of the pole.
September 18, 2025 at 4:04 PM
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Harbor seal doing its thing in Valdez Harbor.
Gray blue water (full of glacial sediment) fills most of the image, with a gray wooden dock in the top center of the scene. There are wavy reflections of boat masts in the water. In the bottom center, a gray and black spotted seal head is popping out of the water. You can make out rest of the seal's body beneath the surface.
September 17, 2025 at 3:50 PM
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A campaign GNSS site above an increasingly colorful Copper River Valley. The mountain at the center of the photo is Mount Blackburn, an eroded shield volcano and the tallest peak in the Wrangells. 20 years of surveying this benchmark and I've never seen Blackburn from here before. Gorgeous day. ⚒️🧪🌋
A yellow tripod with a white GNSS antenna on top sits among fall foliage with evergreens on the left and yellow shrubs on the right. A river valley with a large river sits below the ridge the site is on. More green and yellow trees stretch behind the river. In the distance, a triangular ice covered mountain sits. The sky is very blue. A river runs through a valley flanked by hills covered with dark evergreen tress and yellowing deciduous trees. In the distance, a triangular ice and snow covered mountain sits. Lower hills sit in front of it.
September 17, 2025 at 2:55 AM
julieelliott.bsky.social
A tribute to the toughness and longevity of Trimble Zephyr Geodetic GPS/GNSS antennas: 18 years after the goat incident mentioned below, I just used the same antenna to set up a campaign survey site in another part of Alaska. Still tracks satellites just fine! #geodesy ⚒️🧪
A photo of a campaign GPS/GNSS site. A yellow and black tripod takes up the lower part of the picutre. A green tribrach and gray optical plummet (for leveling) are attached to the top of the tripod. A white circular antenna is attached to the optical plummet. The edge of the antenna facing the camera says "Trimble" in blue letters. Just above the words are two bite marks made by a very curious and naughty mountain goat years earlier.
September 15, 2025 at 10:46 PM
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A green comma butterfly taking a break on an interpretive sign along the Edgerton Highway between Kenny Lake and Chitina. Commas hibernate and overwinter in Alaska, making them tougher than many people.
An predominately orange and brown butterfly with ragged looking wings sits, with wings outstretched, on an interpretive sign about the Copper River watershed.
September 15, 2025 at 6:31 PM
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The Copper River (open the picture to see the full panorama) from the Edgerton Highway between Kenny Lake and Chitina.
A panorama of the Copper River, a large river in the Wrangell Mountains. The Copper is a braided river, and a number of sand bars and winding streams leading into the main pathway are seen. The river valley is bordered by cliffs of sediment deposited by Glacial Lake Ahtna. Trees cover most of the slopes (with some bare sediment peaking out in places) and are a mix of evergreen and deciduous, with the latter in the process of turning gold.
September 15, 2025 at 3:42 PM
julieelliott.bsky.social
A large mural showing penguins commuting at the Silver Spring Metro station. The world needs more murals like this.
A painted mural showing different kinds of penguins lining up at machines to buy metro tickets and passing through turnstiles to get to the train platform. There is a glassed in information booth in the center manned (birded?) by two penguins. On the platform, there is a sign directing the penguins to the different train lines. The floor the penguins are walking on is red hexagonal tile. The next part of the mural shows more of the platform as well as a black and white train with an "M" on the side. Penguins are walking to and entering the train. You can see through the doors and windows of the train and many penguins are already seated. Some have newspapers. A mural section that shows the inside of the train. An advertisement for some sort of bottled drink featuring a penguin in sunglasses is on the wall. There is also a route map on the wall. Some penguins are reading the paper, one is doing the crossword (how is he holding the pencil??), and some are talking to their neighbors.
August 27, 2025 at 12:43 AM
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3-component ground motion visualization of the Kamchatka earthquake from EarthScope. Look at those seismic waves go through! ⚒️🧪
ds.iris.edu/spud/gmv/233...
July 30, 2025 at 1:45 PM
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Map showing today's earthquake (now 8.8), the earthquakes of July 20, and historic M7.5+ events along the subduction zone offshore Kamchatka. ⚒️
Map of the Kamchatka Peninsula region with recent and historic earthquakes. Focal mechanisms (from USGS) are shown for the July 20, 2025 sequence and the M8.8 earthquake of July 29, 2025. Yellow shows M7.5 - 7.9 events, orange M8-8.9 events, and red the 1952 M9 event.
July 30, 2025 at 1:59 AM
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Happy 4th anniversary to the M8.2 Chignik earthquake, the largest (so far?) event in a complex earthquake sequence along the Alaska Peninsula segment of the Alaska subduction zone that keeps on giving more. The most recent event was an oblique strike-slip event in the upper plate on July 16. ⚒️
Small map in corner shows Alaska with a red box around the Alaska Peninsula showing the main area of interest for the earthquake sequence. The main map shows the Alaska Peninsula region with colored regions denoting different amounts of coupling along the subduction zone (how stuck together the plates are), dark orange shapes outlining rupture areas of past large earthquake (1964 M9.2, 1938 M8.3, 1946 M8.6, 1948 M7.1), and light orange shapes outlining the rupture areas of the two largest earthquakes in the recent sequence (July 22, 2020 M7.8 Simeonof and July 29, 2021 M8.2 Chignik). Focal mechanisms are drawn for all five earthquakes in the recent sequence. These mechanisms show that the 2020 M7.8, 2021 M8.2, and July 16, 2023 events had thrust motion while the October 19, 2020 M7.6 Sand Point event and the July 16, 2025 event had oblique strike-slip. There is a legend in the lower right corner explaining the color scale for the coupling. All earthquake dates are in UTC.
July 29, 2025 at 7:22 PM
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The MSU undergraduate geodesy interns presented their projects at a symposium on campus yesterday. They've accomplished a great deal in the past seven weeks and they all did an excellent job talking about geodesy and their research. I'm looking forward to seeing what they do in the future! ⚒️🧪
A man standing next to a poster titled "Comparing Hydrological Deformation Models to GPS Data in and around Kyrgyzstan". A woman standing next to a poster titled "An Initial Assessment of Data Quality and Signal Sources at GNSS Stations in Alaska's ACORN System". A woman standing next to a poster titled "A Geodetic Look at the Tectonic Kinematics and Block Motion in Eastern Russia and Western Alaska". Top: A woman standing next to a poster titled "Using Geodesy to Understand the Hydrologic Variations in Costa Rica". Bottom: A man standing next to a poster titled "GPS and the Amazon".
July 24, 2025 at 6:06 PM
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Updated with aftershocks (blue dots). The aftershocks (~50 so far) are concentrated in a band between Wednesday's M7.3 event and the 2020 M7.6 Sand Point earthquake. Details on sources in the alt text. ⚒️
Map showing earthquakes, past ruptures, and aftershocks from the July 16 M7.3 earthquake along the Alaska Peninsula. Five large earthquakes (7.2-8.2) have occurred since July 2020. Blue focal mechanism shows a healthy amount of strike slip and marks July 16's event. Red contours show past rupture areas for large earthquakes. Black contours show 1-m slip intervals for the 2020 M7.8 Simeonof earthquake (Xiao et al., 2021). Purple contours show 1-m slip intervals for the 2021 M8.2 Chignik earthquake (Elliott et al., 2022). Light blue and cyan contours show possible 1-m slip intervals for 1938 M8.3 earthquake (Freymueller et al., 2021). Gray shading shows geodetic coupling estimates. 1.0 means plates are fully locked together; 0 means plates are freely slipping past each other. Blue dots are aftershocks from the July 16 event. Dark gray lines show upper plate faults in the Sanak and eastern Shumagin segments of the subduction zone (Kahrizi et al., 2024). All focal mechanisms and aftershock locations are from the USGS catalog.
July 18, 2025 at 7:36 PM
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Quick map of M7.3 earthquake offshore the Alaska Peninsula. Today's earthquake (green) has a very similar focal mechanism to the M7.8 2020 Sand Point event, which was dominantly strike-slip but caused a tsunami. Based on depths of mainshock and early aftershocks, could be an upper plate event. ⚒️
Map showing earthquakes and past ruptures along the Alaska Peninsula. Five large earthquakes (7.2-8.2) have occurred since July 2020. Green focal mechanism shows a healthy amount of strike slip and marks today's event. Red contours show past rupture areas for large earthquakes. Black contours show 1-m slip intervals for the 2020 M7.8 Simeonof earthquake (Xiao et al., 2021). Purple contours show 1-m slip intervals for the 2021 M8.2 Chignik earthquake (Elliott et al., 2022). Light blue and cyan contours show possible 1-m slip intervals for 1938 M8.3 earthquake (Freymueller et al., 2021). Blue dots are continuous GNSS sites. Gray shading shows geodetic coupling estimates. 1.0 means plates are fully locked together; 0 means plates are freely slipping past each other.
July 16, 2025 at 9:56 PM
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For #WorldOrcaDay, here are some video clips of an orca family I encountered while doing campaign GPS measurements via boat around Prince William Sound, Alaska in 2009. The calf got brave and did a little spy hop to check us out more closely. Maybe it wanted to learn geodesy?
July 14, 2025 at 9:34 PM
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Obviously, black oystercatchers are the superior oystercatchers. They hang out in fjords near the end of glaciers and pose in extremely photogenic ways.
A black shorebird with an ovalish body, a long orange bill, and pink legs poses regally in front of a chunk of glacier ice sitting on a rocky beach. In the background, more ice chunks float in gray blue water. The bird is daring you to even think that any other shorebird can compare (if you take that dare, you're wrong).
July 12, 2025 at 1:51 PM
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Earth Science solicited opportunities are very sparse this year. ⚒️
1.4 Solicited Opportunities Program elements solicited in Appendix A include: • A.2 Earth Venture: TROPICS and PREFIRE Science and Applications Teams; • A.3 NASA ISRO Synthetic Aperture Radar (NISAR) Mission Research and Applications Science Team; • A.4 Rapid Response and Novel Research in Earth Science (RRNES) • A.5 Earth Venture Suborbital-4 Snow4Flow Science Team • A.6 Earth Venture Suborbital-4 Landslide Change Characterization Experiment Science Team; • A.7 Water Quality Applications; • A.8 Water Resources Applications; • A.9 User-Centered Applications with Large Earth Foundation Models; • A.10 INNOVATE.
July 10, 2025 at 3:49 PM