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Penny Wieser @pennywieser.bsky.social · 1d

He then decided to tell me ebikes have to stop at stop signs. Sir, this happened in the middle of a street. Jesus christ, this is why no one reports stuff to the police.

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Penny Wieser @pennywieser.bsky.social · 1d

Infact he kept telling me it wasn't possible for a car to turn left onto me. Why can't you use some intuition that if street view says a pic was taken in 2022 in a city putting in new bike infrastructure, maybe it's changed?! Surely the police have up to date maps

Penny Wieser @pennywieser.bsky.social · 1d

I said 'you mean cars hitting ebikes?', he said it was so clear he thinks a car cannot be at fault. He was looking at street view which has an old road layout 'maybe the guy didn't know there was a bike lane'. Sir, the road was painted bright green and has been for a year, he lives there...

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Penny Wieser @pennywieser.bsky.social · 1d

I naively thought the police would want to hear my side of a car left hooking me. Victim shaming 100%. Moment I said I was on an e bike the officer said 'thats a car, you have to follow the rules of the road'. Sir, I was left hooked in a bike lane, travelling along. 'we have lots of ebike crashes'..

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Penny Wieser @pennywieser.bsky.social · 2d

I saw it coming as he began to turn and did slow down, but couldn't stop fast enough and a last minute swerve meant I went over the handlebars. Skinned palms are so sore for not looking too bad injury wise.

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Penny Wieser @pennywieser.bsky.social · 2d

Two bike accidents in 2 years, both cycling home from office hours. Can't decide if we should ban cars or ban office hours. Driver left hooked me across a two way cycle lane without even looking in his mirrors. Also second crash where helmet saved my head. #WearAHelmet #Lookinyourgoddamnmirrors

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Penny Wieser @pennywieser.bsky.social · 6d

I also feel many of these numbers are entirely fabricated. You say 3 weeks to decision? Explain why every paper I've ever have submitted to you has sat on the editors desk for 4-6 weeks. I don't believe I'm that much of a statistical anomaly

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Penny Wieser @pennywieser.bsky.social · 8d

We suggest that at both volcanoes the mush piles are as large as they can be, adding more olivine causes material to flow into the rift zones, and they are unable to get any larger without this happening. Overall, we think the plumbing system is dominated by one main reservoir at 3-5 km depth.

Figure 12: Schematic diagram of Mauna Loa’s plumbing system informed by FI barometry, EBSD measurements, and geophysical constraints. Most of the olivine crystallization and magma storage occurs at ~2–6 km depth (likely centered at ~ 3 km). Olivine crystals with a range of Fo contents grow at variable depths in the reservoir. A proportion of these settle into mush piles, where gravitation loading results in intracrystalline deformation. Some of these olivines are remobilized and erupted as antecrysts, while others continue to migrate downrift, forming texturally mature dunites (e.g. sample 66, Gaffney, 2002). The exact location of where olivines become extremely deformed is unknown, so is shown schematically. Based on the tremor locations of Maher et al. (2023) extending upwards from ~3 km bgl beneath the 2022 eruption site, and the dyke injection at 4–8 km modelled by Amelung et al. (2007), we suggest that rift zone eruption sites are fed by dyke intrusion laterally into the rift zone, followed by near-vertical transport to the surface. The source of the lower Mg# orthopyroxene and low Fo olivines in summit eruptions is unclear; our limited FI data is consistent with storage at the top of the reservoir, but a second, shallower dike is hard to rule out (e.g. Lynn et al. 2024, Ellis et al., 2024).

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Penny Wieser @pennywieser.bsky.social · 8d

Interesting, the degree of deformation (quantified by the grain orientation spread or linear intercept distances) and the proportion of diferent fabrics was very similar to Kīlauea. This is surprising - Mauna Loa is bigger, has been active much longer, so should have a more accumulated olivine.

Comparison of deformation characteristics at Mauna Loa and Kīlauea. a) Cumulative distribution function showing the GOS for all grains with an equivalent radii > 100 µm. Individual Mauna Loa eruptions are shown as dotted lines. b) Histogram of GOS values for grains identified as visibly deformed at both volcanoes. The black horizontal lines at the top show the difference in GOS values for the same grain mapped on the Symmetry S3 (used for Mauna Loa) vs. the Bruker Flash (used for Kīlauea). c) Linear intercept distances for each volcano. The inset figure shows one example of how linear intercept distances are defined. d) proportion of each slip system classified using the methodology of Wieser et al. (2020).

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Penny Wieser @pennywieser.bsky.social · 8d

We also looked at olivine deformation systematics. The picrites in particular show beautiful subgrains forming. By looking at the strike of subgrain boundaries, their weighted burgers vectors, and misorientation axes, we were able to identify the olivine slip systems responsible

Signatures of deformation in Mauna Loa olivines. The leftmost column shows an EBSD map with each pixel colored using an inverse-pole figure (IPF) key (inset) where the color shows both the magnitude and direction of the deviation from the mean orientation of the grain (defined as white), with black colors showing deviation in orientation from the mean by more than 3°. Deformation intensity visibly decreases with decreasing GOS from a-c, shown by colors getting less intense, and showing a narrower range of hues. The central column shows the WBVD, with [100] directions as blue, [010] as green, and [001] as red. Note, this is different from the WBVD color key used in Wieser et al. (2020), but this cannot be changed in the software Aztec Crystal. The rightmost column shows the misorientation axes across the black subgrain boundaries marked on the IPF map. The colorbar shows the intensity of the coloring, e.g. a value of 16 means the orientations are 16X more concentrated in that region than elsewhere.

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Penny Wieser @pennywieser.bsky.social · 8d

The more observant will notice there is a LOT of scatter in SO2 mol%, and at a given pressure, some have SO2 and some dont. We think this is because of the sluggish diffusion of SO2, and rapid FI sealing off. Sarah Shi did a great job of modelling this. Takes minutes to get SO2 into the FI.

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Penny Wieser @pennywieser.bsky.social · 8d

The higher mol% SO2 at a given pressure vs. Kīlauea is explained by SulfurX, and XANES measurements by Saper showing higher S6+ proportions. The early degassing accounts for the otherwise confusing precursory SO2 emissions reported by Ben Esse. I was so excited I saw this! doi.org/10.1007/s004...

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Penny Wieser @pennywieser.bsky.social · 8d

The most exciting result is the fact that we found lots of SO2 in our Raman spectra - it is typically stated that SO2 only degasses in the upper few 100m in Hawaii (cyan DCompress model). Our data suggests it starts degassing at a few km. This is backed up by newer models (e.g. SulfurX)....3/N

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Penny Wieser @pennywieser.bsky.social · 8d

Our fluid inclusion storage depths are remarkably consistent across eruptions spanning 10 kyrs, and align extremely well with geophysical estimates of magma storage. They are a bit deeper than Kīlauea (centered at 3 km vs. 1-2 km). Seems shield stage magma storage is stable once established. 2/N

Distribution of pressures and depths obtained from FI. a) We show each eruption as a violin plot, with a horizontal line and an offset dot representing each individual FI. b) FI depths and pressures from Kīlauea for comparison (data from the 2018 eruption of Kīlauea from DeVitre and Wieser, 2024, and the 2023 eruption from DeVitre et al., 2024). c) All non-xenolithic FI from Mauna Loa combined (in grey). We also show just FI with no SO2 peaks (in cyan). d) Compilation of geophysical estimates of magma storage (Amelung et al., 2007; Decker et al., 1983; Johnson, 1995; Varugu and Amelung, 2021; Yun et al., 2005).

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Penny Wieser @pennywieser.bsky.social · 8d

Second open access Mauna Loa paper available! Here we investigate storage depths and degassing systematics using fluid inclusions, and olivine deformation using EBSD in lavas and tephras from 7 eruptions (1852-2022). TLDR: SO2 degasses earlier than expected doi.org/10.1007/s004...

Pictures of fluid inclusions in olivine and pyroxene

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Penny Wieser @pennywieser.bsky.social · 9d

I've never understood the logic for excluding folks who did masters first.

Penny Wieser @pennywieser.bsky.social · 11d

The actual carving pumpkin bit isn't unusual to us so much as the fact that the grocery store has 20 species of extremely nobbly and inedible things that people don't carve, just buy as decorations!

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Penny Wieser @pennywieser.bsky.social · 12d

My first Halloween with housemates in Oregon, I told my housemate she had accidently left some vegetables on the front step, did she want me to bring them in? She had to explain it was for Haloween. I'm not surprised this squash was so hard to cook - I guess toughness is a feature as a decoration

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Penny Wieser @pennywieser.bsky.social · 12d

Last week my husband came back with a 'squash' for dinner which turned out to be the hardest, toughest object known to man. Having come back from the store today, I see he fell into the 'these gourds out front must be edible' trap for foreigners, not realizing Americans buy them as decorations.

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Penny Wieser @pennywieser.bsky.social · 15d

Way too hot in Berkeley this evening (33C), so headed down to spend a few hours in the amazing microclimate at the marina (21C). Bay area temperature gradients over 3 miles are something else. Caught an awesome sunset too.

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Penny Wieser @pennywieser.bsky.social · 15d

We suggest that they form through melt-mush reaction in a olivine-dominated cumulate. Thanks to my great student Berenise, help from bluesky coauthors @alexbearden.bsky.social and @cljdevitre.bsky.social + many more!

Figure 10: Schematic diagram showing one possible origin of the observed poikilitic textures. Mineral colors are schematic based on appearance in XPL. a) Euhedral olivine settles into a mush pile. b) Accumulation of additional olivine on top results in deformation in some samples (e.g. 48g). The degree of olivine deformation varies, likely based on the random motion of force-chains through the mush and complex loading as a result of complex crystal shapes. c) Intrusion of melts with a different composition (perhaps more SiO2-rich) result in the reaction Ol+Liq->Opx, causing preferential resorption of olivine and precipitation of orthopyroxene (d). Orthopyroxene growth must occur in an environment with a low nucleation rate relative to the growth rate, explaining the optical continuity of the orthopyroxene across cm-scales. This dissolution also results in rounding of the olivine grains, and loss of olivine-olivine contacts (as seen in d).

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Penny Wieser @pennywieser.bsky.social · 15d

The only other interesting thing to say - these textures were originally intepreted as co-crystallization of Opx and Ol. But it becomes apparent with thin section scans the Opx are large oikocrysts, enclosing rounded olivines.

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Penny Wieser @pennywieser.bsky.social · 15d

Opx stability at low pressures at Mauna Loa is stabilized by the higher SiO2 content of these melts than
Kīlauea. Depending on the exact FC path, primary melts could have even higher SiO2, helping even more, pushing Opx stability to lower pressures.

a) shows different FC paths for Mauna loa, c) at bottom shows Ol-Opx stability field for these different compositions - for higher SiO2 contents, Opx stability shifts to shallower pressures

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Penny Wieser @pennywieser.bsky.social · 15d

So in summary, we trust fluid inclusions more than thermodynamics given the lack of experimental constraints at these P-T-X conditions. However, thermo also isnt inconsistent with our suggestion these xenoliths came from 2-6 km rather than super deep depths.

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Penny Wieser @pennywieser.bsky.social · 15d

Another way we can test this - Take Opx bearing experiments and ask each model 'do you stabilize Opx'. The answer should be yes. Sadly, at <5 kbar, the models dont do a great job of Opx stability (a). Reflecting a lack of experimental constraints at the P-T conditions of interest (c-d).

Figure assessing the performance of different thermodynamic models. a) Experiments are grouped by pressure bin. The y axis shows the % of experiments containing orthopyroxene where the thermodynamic model correctly predicted orthopyroxene stability. If there were 10 orthopyroxene bearing experiments in a pressure bin and the model only saturates orthopyroxene in two of them, the axis would read 20%. b) Comparison of the Mg# measured in the experiment orthopyroxene (x axis) and the Mg# of the orthopyroxene predicted by the thermodynamic model (y axis). c) P-T conditions of orthopyroxene-bearing experiments in LEPR. Symbols colored cyan pass our compositional filter (are similar to Mauna Loa melts in MgO-SiO2 space), while those in red fail this filter (see Supporting Fig. S22). The pressure-temperature conditions inferred from fluid inclusions and their host crystals are shown (grey dots = lava and tephra samples from Wieser et al, this issue). d) Same plot for all experiments in LEPR, including those that do not stabilize orthopyroxene. Pink dots fail the Si-Mg filter, blue dots pass it.

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