I listened to a really interesting Ezra Klein podcast about chronic pain treatment and the importance of taking a whole body approach. The guest’s main point is that pain originates with an injury or illness, but the patient’s experience of it can be influenced by their day to day life, mental health, supportive care, and levels of stress. I wish I could express it better, because when I write this out it sounds like I’m saying “it’s all in your head!”, but that is definitely not what she was saying. But it would explain someone having reduced relief from pain medication when they don’t have a biochemical reason to do so.

TLDR Pain is a complex sensation and what people experience is hard to understand.

This is a great observation and a good thing to keep in mind for worldle (would have been helpful for the South Atlantic Island the other day).

One of the weirder concepts to wrap your head around in sedimentology is relative sea level. Sea level at any location can change due to local effects, like heavy glaciers loading the crust, actually bowing it down, or for global effects, like changes in global climate or rate of sea floor spreading. It sounds pretty straightforward, but trying to sort out local vs global effects was really hard and took decades.

On a stable coastline, one where relative sea level has been more or less constant for a long time, sediments fill the basin in the water, and the coastline starts to advance out into where the water was before. This is what deltas do. When you look really closely, they are complicated and jagged too, but not on a regional scale.

On a coastline where there is rapidly changing sea level, particularly rapid rises in sea level, all the smoothed coastline will be underwater, and the new coastline will be jagged.

In Earth’s current state, the poles have experienced rapid, recent (50,000 yrs) changes in sea level due to glacial cycles, AND, the erosional pattern of alpine glacier leads to deep, steep valleys (glacier=sediment bulldozer, river = central conveyer belt), so the squiggliness of the coastline will be even more.

I can only comment from experience cutting glass, rocks, and minerals. When you’re cutting stone or glass, you aren’t really cutting them, you’re grinding a plane through the item. The cutting wheels are made by embedding grains of a much harder material, usually silicon carbide, alumina, or diamond, in a composite matrix. When you try to cut dry, the blade heats, the rock heat, and the blade starts to lose cutting grains, destroying the blade. You also aren’t removing the cut material, so it just packs down along the cut. You can cut dry, but you have to go very slowly and resign yourself to buying new blades.

They are observed all along the Hawaiian chain, with Kea on the ne side of the Hawaiian arch and loa on the sw. I’m not sure what the origin of the geochemical differences are between the two, or the reason there are two tracks. The geochemical differences are in radiogenic isotope ratios derived from decay series like Sm-Nd, U-Pb, and Rb-Sr. In mantle derived rocks there are variations attributed to different mantle components, usually considered to represent recycled crust that was carried to the deep mantle, entrained in a plume, and preferentially melted. The kea and loa trends have different proportions of different mantle components.

My reading on the subject is out of date, s may be up to lunch on this, but I think it may mean that the spatial variability of the Hawaiian plume is constant through time, which is pretty neat to think about.

Mauna Loa and Mauna Kea are both shield volcanoes formed by the Hawaiian Plume, but they are in different phases of life for volcanoes of this type. Mauna Loa is in active shield building, where you have large volumes of silica-poor lavas with low viscosity with frequent eruptions. The eruptions occur both from the central, summit vent, and from fissures along the flanks of the mountain. Mauna Kea is currently dormant and has entered the post-shield phase. During this phase lavas become more silica rich, with higher viscosity, and usually have a higher concentration of water, CO2, and SO4 in the magma. Higher viscosity lavas with higher volatile contents are more explosive, gases the exsolve from lava as it rises cannot escape like bubbles in a pot of boiling water. They grow in the lava, becoming bigger as lava rises to the surface. This makes the lavas less dense, making them ascend faster, and eventually when lava hits the atmosphere, they explode, creating cinders.

You can also get cinder cones during active shield building, but it isn’t as common, and since there are so many lava flows happening all the time, the landscape is constantly being covered by new flows and any surface record of cinder cones are lost. Mauna Kea has not been active since 4000 years ago, though it is likely to become active again at some point in the post-shield stage.

An interesting detail about Hawaii is that there are actually two trends of volcanoes, called the Kea and Loa trends, that can be identified by rock chemistry. On the big island Kohala, Mauna Kea, and Kilauea make up the Kea trend, and Hualalai, Mauna Loa, and Loihi make up the Loa trend.

Edited to add some nots that were lost.