Finite Element Method vs Boundary Element Method

Feedbacks between Volcanism and Climate Change

Figure 1: Contours of Volcanic Eruption Events from 0 - 40 ka

Contoured eruption frequencies. (a) The average number of volcanic events per ky observed during the glacial (40–20 ka) and (b) the average across longitude. Longitudinal averages only include points within 5° of a volcano and are subsequently smoothed with a window spanning 15° in latitude. (c,d) are similar to (a,b) but for the deglacial (18–7 ka), and (e,f) are for the late Holocene (5–0 ka). Dots indicate volcanoes. Frequency contours indicate the average number of volcanic eruptions occurring per thousand years within a length scale of 500 km.

(Huybers and Langmuir, 2009)

Figure 1: Frequency Plots of some Informations 0 - 40 ka

Plots showing the frequency of CO2 emissions, CO2 in the atmosphere, volcanic eruptions, and sea level. 

(Huybers and Langmuir, 2009)

Fig. 3Bathymetry at a section of the Australian-Antarctic Ridge.

A region of consistent bathymetry is indicated between the black lines (top right) and is shown in profile (bottom left, blue) after converting off-axis distance to an estimate of time. Time is zero at the approximate ridge center. Also shown is bathymetry after filtering frequencies outside of 1/150 ky^–1and 1/10 ky^–1 (green), and simulated bathymetry (black, for U₀ = 3.3 cm/year and K₀ = 10⁻¹³ m²). Spectral estimates (bottom right) are shown for the unfiltered bathymetry (blue) and model results (black), where the latter are offset upward by an order of magnitude for visual clarity.       Vertical dashed lines indicate frequencies associated with 100ky late-Pleistocene ice ages, obliquity, and precession. Axes are logarithmic. Statistical significance is indicated by the black bar at the top right of the panel: spectral peaks rising further than the distance between the mean background continuum (corresponding to the black dot) and 95th percentile (top of black bar) are significant.
(Crowley et al., (2015))

Mauna Loa Project

Sulfur Isotopes of Pallasites in the context of Iron meteorites

A and B attributed to Antonelli M.A. (2014) PNAS, 50, 17749-17754.
 

The Gorgona Island Komatiite: A Unique Phanerozoic Ultramafic Volcanic

Figure 1: Geologic Map of the Island of Gorgona, Colombia

Figure 2: Location of Gorgona off the coast of Colombia

THBI of Body Wave Travel Time and Surface Wave Dispersion

Figure. Different methods of processing seismic record.   Due to their different physical properties, seismic records can be separated into several data types and be analyzed through varies methods. These data types provides a complementary constraint on Earth’s seismic structure, however, because of the data uncertainties in these measurements, a single best-fit model may not be required or even allowed in most cases.

shear zone localization in planetary lithospheres

Behavior of Mo and other chalcophile elements during igneous differentiation - Kilauea Iki Lava Lake

Proposed Project - Capital Area Seismometers in Schools

Figure 1 -  CASS - Proposed station locations relative to high school locations
 (station scale not to size) One in four Earthscope USArray seismometers
(purple circles)  will be left in this area.

Figure 2 - CASS - Proposed station locations relative to earthquake location (magnitude >2)
(station scale not to size) . Earthquake magnitude scaled by size of circle (bigger circle
 indicates larger earthquake) (station scale not to size) One in four Earthscope USArray
seismometers (purple circles)  will be left in this area.

Urban Watersheds: An Outdoor Laboratory

Volcano Spacing on Io

Bouguer Gravity Anomaly

Newton Fluid

Understanding the delta notation

Inverse Square Laws

flexural rigidity of a plate (e.g. the lithosphere)

Bayes' Theorem

Idealized Plume Ascension Rate (and Lava Lamps)

Particle Reynolds Number for Sediment Transport

General Form

Specific Form

Empirical Geoxybarometer Using V paritioning

Olivine Control Line to determine V content of the melt:

Batch Melting and Fractional Crystallization

S wave velocity from the apparent incidence angle

Molten Rocks Might Have Changed the Earth's Voice

Rocks are NOT that hard stuff

As is known to all, the ice becomes water at a certain temperature. We call that procedure “melting”! Although it’s not usually seen in everyday life, melting also happens in rocks. A pretty good example of the molten rock is the lava coming from the volcano (see figure 1).

                                                       Figure 1: Floating melt rock!

In fact, the temperature in the Earth increases with the depth. When the temperature gets high enough (at a depth about 100 km underground), some part of the rock starts to melt. Scientists use an advanced technique called X-ray imaging to take a close look at the partially molten rock sample, see figure 2. By intuition, we can imagine that the melting procedure would make the rock not so hard as before.

Figure 2: Images of molten rock samples with different amount of melt between the rock grains. There are four rock samples shown here, A, B, C, and D. They are tiny rock cubes with edge length of 0.14 millimeters. The opaque stuff in gray is the melt; the transparent part is the solid rock that hasn’t been molten; and the red area refers to the melt boundaries at each cube face.

Listen to sound inside the Earth

However, properties of the molten rock are still not totally clear. A better understanding of that would help us find answers to other problems in Earth science, for example, the “anomalous sound” geoscientists hear from the Earth. When people talk to each other, we hear the voices, and we get information from that. The Earth also talks. Earthquakes generate “earthquake sounds” (terminologically called seismic waves) that travel though rocks and fluids. Earthquake sounds, i.e. seismic waves, have different traveling speeds in different materials. By listening to the sound from inside of the Earth, seismologists tell where the “sound” is from and what kind of materials it might have traveled through. And that is how we get the information about the Earth interior. Figure 3 shows how our Earth looks like in view of the seismic wave speed at different depths.

Seismic wave speeds rely on the property of the material which the wave travels in. Generally, the harder and denser the material is, the faster the wave travels in it. As depth increases, the rock density gets higher, so the velocities, normally, should also increase. But a strange thing happens at depth around 100 km which we call a Low Velocity Zone (LVZ). As we can see in figure 3, there is a velocity decrease at the LVZ. Why do we have this? What changed the Earth's normal voice? There is much debate on this topic, and some scientists are trying to relate this with partial melt. As depth increases, the temperature also increases. At LVZ, the temperature gets high enough, and the rocks start melting. The melt softens the rock and causes seismic wave velocity decrease.

Figure 3: The two colored curves respectively represent the velocities of two different types of seismic waves along the depth. The dashed lines show the depth of some interesting zones. Here in this article, our interests focus on the depth about 100 km, where the seismic velocities have an unexpected decrease. That area is called the Low Velocity Zone (LVZ).

The melt shape and amount are supposed to have a direct effect on the velocity. But scientists are still looking for the detailed relationship between the melt property and the seismic velocity change. One way to do this is to simulate how the wave travels through the molten rock, and then compare the calculated velocities with existing observations. The simulation work goes on computers, but there are still a lot of issues waiting for clever solutions.