Seismic moment tensor catalog for Uturuncu volcano, Bolivia

We present seismic moment tensor solutions for 63 events at Uturuncu volcano, Bolivia. Moment tensor solutions were generated using body waves and surface waves. The best solution (M0) was obtained through a grid-search in moment tensor space using the "cut-and-paste" (CAP) approach of Zhu and Helmberger (1996) and Zhu and Ben-Zion (2013). The files here are part of the PhD thesis work by Celso AlvizuriThis work was supported by the National Science Foundation (EAR-1215959 and EAR-0909254)

Moment tensor catalog results for nuclear explosions, volcanic events, and earthquakes

Using seismic waveform data, we determine seismic moment tensor solutions for 12 earthquakes and 17 nuclear explosions at the Nevada Test Site, 3 cavity collapse events, 63 events at Uturuncu volcano (Bolivia), and 21 earthquakes in Alaska. We convey uncertainties in the solutions by displaying a probability density function for source type and by calculating a confidence parameter.This project was supported by Air Force Research Laboratory (contract FA9453-15-C-0063) and by the National Science Foundation (grant EAR-1215959)

Seismic moment tensor results for nine events in the North Korea region

We determine moment tensor solutions for nine events in the North Korea region. This is a supplement for a published manuscript by Alvizuri and Tape (2018).This project was supported in part by the Swiss National Science Foundation (grant PP00P2_157627: OROG3NY) and by the U.S. Air Force Research Laboratory (contract FA9453-17-C-0025)

Deciphering Okmok Volcano's restless years (2002-2005)

Thesis (Ph.D.) University of Alaska Fairbanks, 2015Okmok Volcano is an active island-arc shield volcano located in the central Aleutian islands of Alaska. It is defined by a 10-km-diameter caldera that formed in two cataclysmic eruptions, the most recent being ~2050 years ago. Subsequent eruptions created several cinder cones within the caldera. The youngest of these, Cone A, was the active vent from 1815 through its 1997 eruption. On July 12 2008 Okmok erupted from new vents located northwest of Cone D. Between 2001 and 2004, geodetic measurements showed caldera inflation. These studies suggested that new magma might be entering the system. In 2002, a newly installed seismic network recorded quasi-periodic ("banded") seismic tremor signals occurring at the rate of two or more episodes per hour. This tremor was a near-continuous signal from the day the seismic network was installed. Although the volcano was not erupting, it was clearly in a state of unrest. This unrest garnered considerable attention because the volcano had erupted just six years prior. The seismic tremor potentially held insight as to whether the unrest was a remnant of the 1997 eruption, or whether it signaled a possible rejuvenation of activity and the potential for eruption. To determine the root cause and implications of this remarkable seismic tremor sequence, I created a catalog of over ~17,000 tremor events recorded between 2003 and mid-2005. Tremor patterns evolved on the scale of days, but remained the dominant seismic signal. In order to facilitate the analysis of several years of data I created a MATLAB toolbox, known as "The Waveform Suite". This toolbox made it feasible for me to work with several years of digital data and forego my introductory analyses that were based on paper "helicorder" records. I first attempted to locate the tremor using the relative amplitudes of the seismograms to determine where the tremor was being created. Candidate tremor locations were constrained to a few locations along a corridor between Cone A and the caldera center. I then determined theoretical ratios between a reference station and stations nearby the candidate sources. Results suggested that the signal originated in the shallow portion of the corridor connecting the surface of Cone A to the top of the central magma chamber. This study also suggested that the source migrated along this corridor. I integrated the tremor patterns with other studies and proposed that heat and pressure from continued injections of magma were responsible for maintaining an open venting system at Cone A. The tremor resulted from the boiling of a shallow hydrothermal system in the vicinity of Cone A and volatiles potentially coming from the magma itself. The tremor catalog demonstrates that the seismic signal waned during the study period suggesting that fewer fresh volatiles entered the system, which may have allowed the pathways connecting the magma and volatiles to the surface to close up. By the time new magma entered the system in 2006, this network of pathways was closed, forcing the volatiles to seek a new exit. In hindsight, the 2003-2005 period of varied and waning seismic tremor, and the inferred end of massive open venting, may have been a pivotal era at Okmok that eventually led to the 2008 eruption

The Economic Thought on Poverty Measurement: From the Nineteenth-Century to the Rediscovering Era

This essay describes the evolution of the Economics of Poverty from the seminal works of Charles Booth and Joseph Rowntree to the Rediscovering Era in the 1960’s. It shows how the leading objectives of its authors changed over the decades. The description is roughly exhaustive, pointing out the way how the leading concepts, many of them frequently used even nowadays, were developed by its authors.Approaches, Poverty Measurement, Techniques