Seamounts, also named guyots after Swiss-American geologist Arnold Henry Guyot

Arnold Henry Guyot (1807-1884) was a Swiss-American scientist [1,2]. He studied in Switzerland and Germany. Influenced by glaciologist Louis Agassiz, Guyot investigated Swiss glaciers. He was a professor of geography in Neuchâtel in Switzerland and later became the first professor for geography at Princeton University in the United States. He published text books in the fields of natural history and geography. His name is now mostly associated with seamounts (extinct volcanoes) found in deep oceans and rising up to a few hundred feet below the sea surface, featuring a smooth platform top. Don and Florence Leet put it this way [3]:

They [the truncated volcanoes] were originally called “tablemounts” or “seamounts,” but the most widely used name now is “guyot,” after Arnold Guyot, a Swiss-American geologist of the mid-19th century. Guyots, like submarine canyons, raise the fascinating question of whether sea level has undergone fluctuations of a mile or more.

Notice that this was written during the years when the theory of plate tectonics and seafloor spreading slowly made its transition from speculation to proof gathering.

References
[1] James D. Dana: Memoir of Arnold Guyot. 1807-1884.[www.nap.edu/html/biomems/aguyot.pdf].
[2] Autorenkollektiv: Lexikon der Naturwissenschaftler. Spektrum Akademischer Verlag, Heidelberg•Berlin, 2000.
[3] L. Don and Florence Leet: Earthquake • Discoveries in Seismology. Dell Publishing Co., Inc, 750 Third Avenue, New York, N. Y. , 10017, USA, 1964; page 124.

Mohole, short for Mohorovičić discontinuity drilling hole

The word Moho stands for the phrase Mohorovičić discontinuity, the boundary between the crust and the mantle inside planet earth. Mohole is short for Moho hole, more precisely for a drilling hole all the way down through earth's crust to or beyond the Moho. Don and Florence Leet described the motivation for drilling that deep and pierce the Moho [1]:

Information on the Moho has been gathered in many parts of the world now. Lava for many if not all our volcanoes may be generated in the region near the Moho. The Moho probably holds the answers to several very important questions about our planet, and probably some we don't even know enough to ask yet. So great is our curiosity about it that there is actually a project for drilling a Mohole down to it for a firsthand sample of what is there.

Project Mohole was suggested in 1957 by Walter Munk, a member of the National Science Foundation (NSF) Earth Science Panel [2]. In a sense, this project was the inverse to the space program. Lack of funding, however, prevented its completion. No access to earth's mantle—then. But recent drilling projects are coming close to deliver Moho and mantle rocks [3].

Keywords: geophysics, drilling, earth's interior, earth's mantle

References
[1] L. Don and Florence Leet: Earthquake • Discoveries in Seismology. Dell Publishing Co., Inc, 750 Third Avenue, New York, N. Y. , 10017, USA, 1964; pages 83 and 84.
[2] Project Mohole, 1958-1966 [www.nationalacademies.org/history/mohole].
[3] R. Monastersky: Drilling shortcut penetrates Earth's mantle [findarticles.com/p/articles/mi_m1200/is_n8_v143/ai_13526575].

Moho for Mohorovičić discontinuity, named after Yugoslavian/Croatian seismologist A. Mohorovičić

Andrija Mohorovičić was born in 1857 inVolosko, an Istrian village on the Adrian Coast. In 1910 he became a university professor in Zagreb, teaching astronomy and geophysics [1]. By studying the spreading behavior of seismic waves registered during earthquakes, he found a velocity discontinuity for those waves. This discovery lead to the conclusion that a boundary exists inside the earth, which separates the crust from the mantle. The boundary became known as Mohorovičić Discontinuity, or Moho for short.

Here is how L. Don and Florence Leet introduce this discontinuity in my favorite booklet on the early history and science of seismology [2]:

When rocks that transmit earthquake waves at one speed lie on rocks that transmit them at a different speed, the boundary where the rocks meet at is called a “discontinuity.” The boundary discovered by Mohorovicic has been named after him, the “Mohorovicic discontinuity.” Since this is quite a mouthful, it is usually referred to simply as the “Moho.” The layer above the Moho is called the earth's “crust” and the layer below it the earth's “mantle.”

Indeed, Mohorovičić is difficult to say, spell and mark up. Moho is a much easier term. Moho also sounds somewhat Hawaiian, underlining its wave and quake association.

Keywords: earthquakes, seismology, boundaries within earth, Croatia

References and recommended reading
[1] Andrija Mohorovičić • Prominent Istrians [www.istrianet.org/istria/illustri/mohorovicic]
[2] L. Don and Florence Leet: Earthquake • Discoveries in Seismology. Dell Publishing Co., Inc, 750 Third Avenue, New York, N. Y. , 10017, USA, 1964; page 83.

The term reverberation explained

The noun reverberation refers to the repetition of sound resulting from reflections of it waves. The phenomenom of reverberation is difficult to explain in terms of physics. My Oxford Dictionary of Physics (2003 edition) only has an entry for “reverberation time”:

The time taken for the energy density of a sound to fall to the threshold of audibility from a value 10⁶ times as great; i.e, a fall of 60 decibels. It is an important characteristic of an auditorium. The optimum value is proportional to the linear dimension of the auditorium.

If something starts reverberating in your head now, you might prefer the following explanation of reverberation by Don and Florence Leet, which I really like since it illustrates the concept in a few vivid sentences:

If sound hits a mountain, wall, or other solid surface some of it bounces back. This bouncing off is called “reflection” or “echoing.” And when it takes place back and forth and up and down in a room, we call it “reverberation.” The great difference between the sound of things in open air and in a room or auditorium is that in the open, there is no reverberation and inside there is.

Keywords: acoustics, sound waves, reflection

Reference
L. Don and Florence Leet: Earthquake • Discoveries in Seismology. Dell Publishing Co., Inc, 750 Third Avenue, New York, N. Y. , 10017, USA, 1964; pages 61 and 62.

Acronym and file extension in crystallography: cif for crystallographic information file or framework

CIF stands for crystallographic information file. It was designed as “a general, flexible and easily extensible free-format archive file; it is human and machine readable and can be edited by a simple text editor” [1]. Plain-text files in CIF format provide a standard for the exchange of crystallographic data. A CIF file contains information such as the chemical name and the composition of a crystalline compound or material, unit cell parameters and lattice coordinates, space group assignment and a reference to the original publication of the data.

The acronym CIF also stands for crystallographic information framework, sponsered and defined by the International Union of Crystallography (IUCr) as “ a broader system of exchange protocols based on data dictionaries and relational rules expressible in different machine-readable manifestations, including, but not restricted to, Crystallographic Information File and XML” [2].

The CIF format is used by fee-charging enterprise as well as open-access services; for example, the Inorganic Crystal Structure Database (ICSD) and Crystallography Open Database (COD) [3], respectively .

Keywords: crystallography, data exchange standard file format, electronic data transmission, ASCII file

References
[1] S. R. Hall, F. H. Allen and I. D. Brown: The Crystallographic Information File (CIF): a New Standard Archive File for Crystallography. Acta Cryst. A 1991, 47, pp. 655-685 [www.iucr.org/__data/iucr/cif/standard/cifstd1.html].
[2] International Union of Crystallography (IUCr): CIF [www.iucr.org/resources/cif].
[3] S. Gražulis et al.: Crystallography Open Database - an open-access collection of crystal structures. J. Appl. Cryst. 2009, 42, pp. 726-729.
DOI: 10.1107/S0021889809016690.

The noun “eutaxy” and the adjective “eutactic”

The words eutaxy and eutactic have Greek roots. The noun eutaxy means “good or established order or arrangement” [1].

The two terms are mostly found in the literature of chemistry, geology and crystallography. In an article on ion packing in crystal structures, M. O'Keeffe explains that the terms were suggested (via private communication) by Mrs. M. Hyde [2]. O'Keeffe proposed to call the arrangements of spheres (atoms, ions) in a periodic lattice eutactic, when the spheres are configured in a close-packing geometry, but without being in contact. G. S. Rohrer uses the term eutactic arrangement as a synonym for pseudo-close packed framework [3]. Identification of the packing type and eutactic framework is critical in naming and classifying crystal structures.

Keywords: sphere packing, structural concepts, density and volume of ionic compounds

References
[1] The Free Dictionary: www.thefreedictionary.com/Eutaxy.
[2] M. O'Keeffe: On the Arrangement of Ions in Crystals. Acta Cryst. A 1977, 33, pp. 924-927. DOI: 10.1107/S056773947700223X.
[3] G. S. Rohrer: Structure and Bonding in Crystalline Materials. Cambridge University Press, Cambridge, UK, 2001; page 145.

Acronyms in sustainable chemistry: CCS and CCR for carbon capture and storage and reuse, respectively

The term carbon capture is commonly used in the context of avoiding or reducing the release of carbon dioxide (CO₂) into the atmosphere. The acronym CCS stands for carbon capture and storage or carbon capture and sequestration. The acronym CCR stands for carbon capture and reuse or carbon capture and recycling.

CCS typically refers to the storage of CO₂ in geological formations. CCR refers to technologies that include winning, purification and use of CO₂. Today, about 110 million tons of this greenhouse gas—less than 0.5% of its worldwide emission—are recycled as raw material for further use as industrial gas or precursor compound in chemical synthesis [1]. Research in the future use of CO₂ as a building block in polymer syntheses, for example, has been discussed and initiated [1,2]. Rational design of new catalysts and photocatalytic approaches may result in the implementation of effective CO₂-consuming processes. However, sustainability of such processes has to be critically evaluated by accounting for the total energy input and the overall CO₂ balance. The fabrication of novel compounds with desired properties can be expected and will result in the fixation of a certain amount of CO2, depending on their lifetime. But this amount is not going to liberate us from the need of finding other means of reducing atmospheric CO2 emission.

References
[1] A. Bazzanalla, D. Krämer and M. Peters: CO2 als Rohstoff. Nachrichten aus der Chemie December 2010, 58, 1226-1230.
DOI: 10.1002/nadc.201075752.
[2] Vom Problem zum Rohstoff? Interview mit Walter Leitner.
[3] CO2NET: Technologien für Nachhaltigkeit und Klimaschutz.