SEMINAR: MGG Student Seminar - Today!

[Monica Arienzo <marienzo@rsmas.miami.edu>]

***MGG STUDENT SEMINAR***

Third Floor CIMAS Conference Room
Today, Tuesday, May 4

12 - 1 pm


Viability of an Earthquake Early Warning System for Regional Events that 
could affect Puerto Rico

Emanuelle A. Feliciano


Abstract

As part of the emergent Puerto Rico and Virgin Island tsunami warning 
system, the Puerto Rico Seismic Network (PRSN) is responsible to provide 
rapid location, and size estimation for seismic events felt in Puerto 
Rico and Western Dominican Republic or any event with potential to 
generate tsunami that could affect Puerto Rico or the Virgin Islands. 
This research is a pilot study that seeks a comprehensive Earthquake 
Early Warning System for Puerto Rico (EEWS) and the Caribbean. An EEWS 
consists of: rapid earthquake location, ShakeMap product, estimation of 
building damage and life loss, and a tsunami wave arrival time 
prediction tool. This research focuses on the ShakeMap tool, which is a 
graphical representation of ground shaking produced by an earthquake. 
There are three types of ShakeMaps: empirical, instrumental and 
community internet intensity map (CIIM). Three seismic events occurring 
in Martinique, Virgin Islands, and Costa Rica are simulated to test this 
method for Puerto Rico and adjacent areas. As input, a topography-slope 
based Vs30 grid is used instead of a geology based Vs30 grid. This 
method could be used to advice communities and local government the 
imminent arrival of dangerous ground shakings and to help saving lives 
and property. Various parameters were tested in order to achieve the 
goal of generating regional ShakeMaps in approximately 5 minutes. There 
were no significant differences between instrumental ShakeMaps and those 
obtained from online felt intensity reports,
therefore, PRSN is now able to generate these regional ShakeMaps in 
approximately 5 minutes.


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Recipe for cooking Persian Salt Lake: a cup of Evaporites, a pinch of
Volcanics and a dash of Carbonates

Arash Sharifi

The geochemistry of salt lakes and salt planes and the role of regional 
geology as a source of elemental input is a controversial topic among 
those who are interested in Iran’s geology. One group emphasizes on the 
role of Neogene (23 Ma-2.5 Ma) sedimentary rocks as a source of 
elements, while others argue that the elements originate from chemical 
weathering of Paleogene (65 Ma-23 Ma) volcanic rocks. The current 
research is an attempt to shed light on the sources of elemental 
contribution of these different types of rocks to Iran’s largest Salt 
Lake, Urumia. The Urumia Lake is a hypersaline (300 g L-1 salinity) 
shallow water body that occupies the lowest area of a closed, 
continental drainage basin in northwestern Iran. This lake is surrounded 
by various rock types of different ages, ranging from the Precambrian 
metamorphic complexes to recent mud deposits.  Mass balance study of the 
elements between silicate fraction of the lake’s sediments and volcanic 
rocks of the region indicates that the lake sediments have higher 
concentrations of Al, Fe, Zn, Cr and V, and lower concentrations of Ca, 
K, Na, Mn, Sr, Ba and P compared with their volcanic sources. The 
chemical index of alteration (CIA) indicates that the silicate fraction 
of lake sediments experienced moderate stages of chemical weathering 
(CIA=60-80). The distribution patterns of anions and cations according 
to total dissolved solids (TDS) of two major water sources to the lake 
(Zarinehrud and Siminehrud rivers) are associated with those of rock 
dominance origin.  In contrast, the anion and cation distribution 
patterns of the lake water and Aji Chay River (major TDS contributor) 
are similar to the waters originating from evaporites.  High Ca+Mg/Na+K 
ratios for Zarrinehrud River indicate that Ca and Mg mainly originate 
from the carbonate rocks of the region, while high Na+K/Total Anion 
ratios for this river suggest aluminosilacate origins for Na and K in 
this river.  Based on the geochemistry of the riverine input to the 
Urumia Lake, the Neogene, evaporite-bearing sedimentary rocks are the 
major contributors to the elemental budget of the lake. Paleogene 
volcanics and Cretaceous carbonates, in contrast, are minor 
contributors. Urumia Lake water can be classified as Na-K-Cl-Mg-SO4 brine.





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