Discussion of “Proposed use of the T phase in tsunami warning systems”*

1951 ◽  
Vol 41 (2) ◽  
pp. 165-167
Author(s):  
L. Don Leet
Keyword(s):  
Dominican Republic ◽  
Pacific Coast ◽  
Sea Water ◽  
Tsunami Warning ◽  
Columbia University ◽  
Warning Systems ◽  
The Pacific ◽  
Short Period ◽  
The Pacific Ocean ◽  
T Phase

Abstract Ewing, Tolstoy, and Press of Columbia University reported that “a striking correlation between the occurrence of a short-period earthquake phase (T phase) traveling through the ocean with the speed of sound in sea water and the occurrence of tsunamis has been observed.” Their statements about the characteristics of T are incorrect in every essential detail. For the Pacific Ocean, they list five tsunami between 1933 and 1946, of which the largest, on April 1, 1946, was generated by an earthquake for which no T was recorded. They neglect to mention the earthquake of January 23, 1938, near Hawaii, which produced the largest T recorded on the Pacific coast to date, but no tsunami. The importance of these outstanding exceptions, errors in reporting the data, and uncertainty concerning the actual number of T phases recorded on the Pacific coast combine to make the evidence for any value of T as a tsunami warning decidedly inconclusive. In the Atlantic, the proposal that T be used as a tsunami warning reduces to an absurdity. Ewing, Tolstoy, and Press state that between 1939 and 1948 “20 Dominican Republic shocks produced T phases,” and that one of them was followed by a definite tsunami. Actually, more than 200 Dominican Republic shocks produced T within that span of years, and many in other Atlantic regions. With one minor tsunami among 200 to 250 T phases, the correlation is not impressive.

scholarly journals Proposed use of the T phase in tsunami warning systems*

1950 ◽  
Vol 40 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Maurice Ewing ◽  
Ivan Tolstoy ◽  
Frank Press
Keyword(s):  
Speed Of Sound ◽  
Sea Water ◽  
Tsunami Warning ◽  
Warning Systems ◽  
Short Period ◽  
T Phase

Abstract A striking correlation between the occurrence of a short-period earthquake phase (T phase) traveling through the ocean with the speed of sound in sea water and the occurrence of tsunamis has been observed. The characteristics of the T phase are described and the data upon which the correlation is based are presented. Although further study is needed, the evidence at hand warrants the inclusion of instruments suitable for recording the T phase in tsunami warning systems. It is quite possible that SOFAR listening stations would be valuable adjuncts in the detection of tsunami-producing earthquakes since they offer the best means of recording the T phase.

Redescription of Mugil setosus Gilbert 1892 with comments on the occurrence of Mugil curema Valenciennes 1836 in the Pacific Ocean (Teleostei: Perciformes: Mugilidae)

Zootaxa ◽  
2019 ◽  
Vol 4671 (3) ◽  
pp. 396-406
Author(s):  
RICARDO BRITZKE ◽  
NAÉRCIO A. MENEZES ◽  
MAURO NIRCHIO
Keyword(s):  
Pacific Ocean ◽  
Pacific Coast ◽  
The Third ◽  
Dorsal Fin ◽  
The Pacific ◽  
Fin Rays ◽  
The Pacific Ocean ◽  
The Western Pacific ◽  
Pectoral Fin Rays ◽  
Pelvic Fin

Mugil setosus Gilbert 1892 was originally described by Gilbert based on specimens from Clarion Island, in the western and most remote of the Revillagigedo Islands, about 1,000 km off the western Pacific coast of Mexico. Examination of the type of material and recently collected specimens from Ecuador and Peru, resulted in the redescription provided herein. Diagnostic characters of the species were mainly: tip of the pelvic fin reaching beyond the vertical through the base of the third dorsal-fin spine, the pectoral-fin rays with ii+13–14 rays, the anterodorsal tip of second (soft) dorsal fin uniformly dark, and an external row of larger teeth, and more internally a patch of scattered smaller teeth, visible mainly in adults 150 mm SL. The expansion of geographic distribution of Mugil setosus and occurrence of Mugil curema Valenciennes 1836 in the Pacific Ocean are discussed. 

scholarly journals A new species of Leptogorgia (Cnidaria: Anthozoa: Octocorallia) from Golfo Dulce, Pacific, Costa Rica

Zootaxa ◽  
2012 ◽  
Vol 3182 (1) ◽  
pp. 65 ◽  
Author(s):  
ODALISCA BREEDY ◽  
HECTOR M. GUZMAN
Keyword(s):  
New Species ◽  
Costa Rica ◽  
Pacific Coast ◽  
Single Species ◽  
San Jose ◽  
Ongoing Research ◽  
Deep Waters ◽  
The Pacific ◽  
The Pacific Ocean ◽  
A New Species

The description of this single species is necessary to facilitate the publication of ongoing research conducted by Rita Vargas at the Museum of Zoology, University of Costa Rica, dealing with the associated microfauna. Presently 24 species of Leptogorgia have been reported for the eastern Pacific, 13 of which have been found in Costa Rica (Breedy & Cortés 2011). Although octocoral surveys have been conducted as part of biodiversity studies, there is no published information regarding the occurrence of this taxon in Golfo Dulce. Here we describe a new species of Leptogorgia and compare it with other Leptogorgia species with similar characteristics. Golfo Dulce is a bay located on the southern Pacific coast of Costa Rica. It is about 50 km long, 10–15 km wide, and covers an area of approximately 680 km². The inner part of Golfo Dulce has a maximum depth of slightly over 200 m with a 60 m deep sill at the opening to the Pacific Ocean (Cortés 1999). It has been considered a tropical fjord because of the bathymetry and the presence of anoxic deep waters (Cortés 1999, Svendsen et al. 2006). Specimens were collected by Scuba diving, preserved in 70% ethanol or air dried, and treated and identified following the current methodology (Breedy & Guzman 2002). The holotype and paratypes are deposited in the Museo de Zoología, Universidad de Costa Rica (MZUCR, formerly UCR), San José, P.O. Box 11501-2060, Costa Rica.

scholarly journals The T phase of shallow-focus earthquakes*

1950 ◽  
Vol 40 (1) ◽  
pp. 25-51 ◽  
Author(s):  
Ivan Tolstoy ◽  
Maurice Ewing
Keyword(s):  
Dominican Republic ◽  
Velocity Of Sound ◽  
Practical Applications ◽  
Short Period ◽  
T Phase ◽  
Shallow Focus

Abstract A short-period phase, 0.5 sec. period or less, traveling through the ocean with the velocity of sound in water has been identified on a large number of seismograms of earthquakes occurring at sea. This arrival was identified on the Benioff short-period seismograms of the Weston, Fordham, and Ottawa stations for a series of Dominican Republic shocks, and on the Benioff short-period seismograms of the Pasadena network of stations and the Mount Hamilton and Mineral stations for a series of major Japanese and Aleutian shocks. The existence of this phase had been noted previously by Linehan, who was at a loss to provide an explanation for them. The mechanism of propagation of the T phase is discussed and several practical applications are described.

A new species of Metaruncina (Gastropoda: Heterobranchia: Runcinida) from Vietnam with a discussion on the so-called rudimentary radula in runcinids

Zootaxa ◽  
2021 ◽  
Vol 4974 (1) ◽  
pp. 197-200
Author(s):  
ALEXEI V. CHERNYSHEV
Keyword(s):  
New Species ◽  
Pacific Ocean ◽  
Coastal Waters ◽  
Marine Biology ◽  
Pacific Coast ◽  
Common Species ◽  
Scientific Center ◽  
The Pacific ◽  
The Pacific Ocean ◽  
A New Species

Marine heterobranch slugs of the order Runcinida comprise 61 species, most of which inhabit the Atlantic Ocean and are referred to the genus Runcina. The Runcinida of the Pacific Ocean have been much less studied to date: only 12 species, from the genera Metaruncina Baba, 1967, Rfemsia Chernyshev, 1999, Runcinida Burn, 1963, Runcinella Odhner, 1924, Pseudoilbia M. C. Miller & Rudman, 1968, and Runcina Forbes [in Forbes and Hanley], 1851, have been described from the region. Metaruncina, Rfemsia, and Runcinida are found in the Pacific Ocean only (Baba 1954, 1967; Burn 1963; Gosliner 1991; Chernyshev 1998, 1999, 2005, 2006). The genus Metaruncina, endemic from the Pacific coast of Asia, includes two species: M. setoensis (Baba, 1954) and M. nhatrangensis Chernyshev, 2005. The latter is the only runcinid described from the coastal waters of the South China Sea, where it was found in the bays of Nha Trang and Van Phong (Chernyshev 2005). During subsequent expeditions to the coastal waters of Vietnam, this species was also recorded from off Tho Chu Island (09°19’N, 103°30’E) and off Nam Du Island (09°43′ N, 104°23′ E). However, in addition to this common species, an undescribed species of Metaruncina was collected. A description of this new species is provided in the present paper. Type material was deposited at the Museum of the A.V. Zhirmunsky National Scientific Center of Marine Biology FEB RAS, Vladivostok, Russia (MIMB). 

JMA’s Tsunami Warning for the 2011 Great Tohoku Earthquake and Tsunami Warning Improvement Plan

2012 ◽  
Vol 7 (sp) ◽  
pp. 439-445 ◽  
Author(s):  
Tomoaki Ozaki ◽  
Keyword(s):  
Pacific Coast ◽  
Early Stage ◽  
Tohoku Earthquake ◽  
Lessons Learned ◽  
Tsunami Warning ◽  
Japan Meteorological Agency ◽  
Improvement Plan ◽  
The Pacific

The Japan Meteorological Agency (JMA) issued a timely tsunami warning three minutes after the 2011 off the Pacific coast of Tohoku Earthquake (the Great Tohoku Earthquake) occurred at 14:49 (JST) on March 11, 2011. However, predicted tsunami heights at the early stage were greatly underestimated. Based on lessons learned from this earthquake, the JMA plans to improve its tsunami warning.

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