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(a) 17,000 kg Wiechert horizontal seismograph installed in the central station Tacubaya. (b) Paper drums of the
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The SISMOMex project represents more than 110 yr of seismological information from Mexico. Its objective is the preservation, search, recovery, systematization, reuse, and dissemination of data and information from the seismograms generated by the Servicio Sismológico Nacional (SSN, National Seismological Service of Mexico) and published material a...
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Context 1
... communicated with the central station in Mexico City around 1988(Pacheco, 2001). Most of the original stations started failing and were abandoned, and the new ones were installed in a configuration of the network focused on central and southern Mexico (Fig. 1). Some of these stations operated and have a corresponding paper seismogram until 2015 ( Fig. 2). At present, the unique station that is still recording on paper is installed in the yard of the Institute of Geophysics of Universidad Nacional Autónoma de México (UNAM ; Fig. 2); it is considered a safety backup, if everything else ...
Context 2
... of these stations operated and have a corresponding paper seismogram until 2015 ( Fig. 2). At present, the unique station that is still recording on paper is installed in the yard of the Institute of Geophysics of Universidad Nacional Autónoma de México (UNAM ; Fig. 2); it is considered a safety backup, if everything else fails. ...
Context 3
... 2009, more than 310,000 paper seismograms were stored in the central seismic station at Tacubaya (Fig. 2), northwest of Mexico City. The conditions were less than optimal. The building had severe leakage, and some of the seismograms got damaged. Acknowledging the historical value and potential of preserving this collection of paper seismograms, the director of the Institute of Geophysics agreed with the head of the SSN, and the head of the ...
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... For the same reasons, the preservation of legacy seismic data is an urgent priority (e.g., Bogiatzis and Ishii 2016;Richards and Hellweg 2020;Hwang et al. 2020;Pérez-Campos et al. 2020). As seismic and acoustic waves propagate over distance, wave amplitude loss occurs from geometrical spreading, attenuation, and scattering, generally resulting in information loss about volcano seismic and acoustic unrest and eruption signals with increasing distance from the volcanic source. ...
Since the 1919 foundation of the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI), the fields of volcano seismology and acoustics have seen dramatic advances in instrumentation and techniques, and have undergone paradigm shifts in the understanding of volcanic seismo-acoustic source processes and internal volcanic structure. Some early twentieth-century volcanological studies gave equal emphasis to barograph (infrasound and acoustic-gravity wave) and seismograph observations, but volcano seismology rapidly outpaced volcano acoustics and became the standard geophysical volcano-monitoring tool. Permanent seismic networks were established on volcanoes (for example) in Japan, the Philippines, Russia, and Hawai‘i by the 1950s, and in Alaska by the 1970s. Large eruptions with societal consequences generally catalyzed the implementation of new seismic instrumentation and led to operationalization of research methodologies. Seismic data now form the backbone of most local ground-based volcano monitoring networks worldwide and play a critical role in understanding how volcanoes work. The computer revolution enabled increasingly sophisticated data processing and source modeling, and facilitated the transition to continuous digital waveform recording by about the 1990s. In the 1970s and 1980s, quantitative models emerged for long-period (LP) event and tremor sources in fluid-driven cracks and conduits. Beginning in the 1970s, early models for volcano-tectonic (VT) earthquake swarms invoking crack tip stresses expanded to involve stress transfer into the wall rocks of pressurized dikes. The first deployments of broadband seismic instrumentation and infrasound sensors on volcanoes in the 1990s led to discoveries of new signals and phenomena. Rapid advances in infrasound technology; signal processing, analysis, and inversion; and atmospheric propagation modeling have now established the role of regional (15–250 km) and remote (> 250 km) ground-based acoustic systems in volcano monitoring. Long-term records of volcano-seismic unrest through full eruptive cycles are providing insight into magma transport and eruption processes and increasingly sophisticated forecasts. Laboratory and numerical experiments are elucidating seismo-acoustic source processes in volcanic fluid systems, and are observationally constrained by increasingly dense geophysical field deployments taking advantage of low-power, compact broadband, and nodal technologies. In recent years, the fields of volcano geodesy, seismology, and acoustics (both atmospheric infrasound and ocean hydroacoustics) are increasingly merging. Despite vast progress over the past century, major questions remain regarding source processes, patterns of volcano-seismic unrest, internal volcanic structure, and the relationship between seismic unrest and volcanic processes.
... The Parral 1928 earthquake was well recorded by the National Seismological Service of Mexico (SSN) seismographic stations at regional distances. Nowadays, the Mexican analogue seismographic collection is stored at the Joint Library of Earth Sciences of UNAM (BCCT), as part of the Sismoteca-SSN project to preserve, digitize and reuse this amount of legacy data (Pérez-Campos et al., 2020). Due to the availability of the Sismoteca-SSN seismographic collection, we have been able to get and use the original 1928 seismograms from the Mazatlan (MZX), Guadalajara (GUM), Merida (MER), Tacubaya (TAC) and Manzanillo (MNZ) stations. ...
... The yellow star represents Parral town well as bulletins, and linking this information to the SSN repository. Seismograms are being carefully scanned and metadata linked to the image, and digital information has begun to be incorporated (Pérez-Campos et al., 2020). ...
Modern analysis of earthquakes depends on digital time series; however, only about 30% of the timespan of recorded seismicity is available in digital format. During the first half of the 20th century, most of the earthquake ground motions in Mexico were recorded by Wiechert mechanical instruments on smoked paper. In this work, we developed and use Tiitba, a new portable multiplatform graphical user interface (GUI) open‐source software coded on python, to vectorize and correct old analogue seismograms. Using this software, we vectorized the 11/1/1928 Parral (M6.3) earthquake seismograms to obtain the constant time‐interval digitized time series for each component and station of the seismogram. Then, we obtained its source focal mechanism using a genetic algorithm methodology. Also, with an auxiliary Tiitba module, we constructed a SEISAN S‐file to relocate the hypocentre of this earthquake. The obtained relocation is about 125 km south of a recently recorded seismic swarm that occurred in 2013, which has a similar focal mechanism to the one that we obtained in this work. Re‐examination of historical earthquakes from legacy seismic data requires reliable vectorization and correction of analog seismograms. Nowadays, computational capabilities allow the development of ad‐hoc programs to perform such analysis. In this work we use Tiitba, our own developed Python based‐software to vectorize, analyze and correct the analog seismograms of the 1928 Parral earthquake towards a focal mechanism redetermination through a Genetic Algorithm method. Also, with an auxiliary Tiitba module, we create a SEISAN S‐file to recalculate the earthquake hypocenter.
... In their report, Flores and Camacho (1922) report three aftershocks. Suárez and Novelo-Casanova (2018) recovered the original seismograms from the National Seismogram Library (Pérez-Campos et al., 2020). There has been a discussion whether the Xalapa event is a crustal earthquake in the TMVB or an intermediate-depth event beneath central Mexico, associated with the subducting Cocos plate. ...
The Mexican National Seismological Service (SSN) was founded on 5 September 1910, in response to commitments made by Mexico to the International Association of Seismology in 1903. The first seismic instruments installed in 1904 were a Bosch–Omori seismograph and a Palmieri seismoscope. The SSN was formally inaugurated on 5 September 1910, a few days before the revolution broke out; a political struggle that lasted over two decades. The SSN was inaugurated with a central station in Tacubaya, Mexico City, and two secondary stations. Wiechert seismographs were selected by the SSN for its budding network. Despite the adverse economic and political situation, the SSN managed to grow and install more stations during the turmoil. Besides the installation of new seismic stations and reporting the location and macroseismic data of earthquakes in Mexico, the SSN staff produced remarkable reports of important earthquakes that occurred in those early years. Notable among these are the detailed reports on the 19 November 1912 and 4 January 1920 earthquakes on the Trans-Mexican volcanic belt. These reports have shaped the estimations of seismic hazard in this highly populated region of Mexico. In the first aftershock studies reported, the SSN took Wiechert instruments to the epicentral areas of a large subduction earthquake in 1907 and to the city of Xalapa, in the vicinity of the 1920 crustal earthquake. With foresight in those early years of seismology, the SSN scientists correctly attributed the 1912 earthquake to a local active fault. The seismograms collected in 1920 confirmed that it was a crustal earthquake and not an in-slab event. Lack of funding and official interest did not permit the modernization of the SSN for many decades. National interest in the Service was boosted by the 19 September 1985 destructive earthquake.
To preserve the analog records of historical earthquakes which occurred in and around Iran in digital form and to make them available for modern analysis techniques that require waveforms, we decided to digitize seismograms of destructive earthquakes that occurred between 1960 and 1990. The seismograms have been recorded at five seismic stations deployed in Tehran, Mashhad, Kermanshah, Tabriz, and Shiraz by the Institute of Geophysics of the University of Tehran (IGUT). The restoration project of the old analog seismograms archived in the IGUT started in 2018. Seismograms were sorted by station and date to create a hardcopy databank, and then those from large earthquakes and their larger aftershocks were chosen for the scanning process. Seismograms of 52 significant earthquakes and their aftershocks with magnitudes greater than 5.0 that occurred in and around Iran were scanned. Besides that, seismograms of several significant and huge teleseismic earthquakes that occurred between 1960 and 1990 were scanned. At present, almost 600 scanned seismograms are available. The current digitization process in IGUT is done manually and is based on waveform vectorization. The provided databank is one of the most important sources of information for research in seismology and active tectonics in and around Iran.
To preserve the analog records of historical earthquakes which occurred in and around Iran in digital form and to make them available for modern analyses techniques that require waveforms, we decided to scan seismograms of destructive earthquakes that occurred between 1960 and 1990. The seismograms have been recorded in five seismic stations deployed in Tehran, Mashhad, Kermanshah, Tabriz, and Shiraz by the Institute of Geophysics of the University of Tehran (IGUT). The restoration project of the old analog seismograms archived in the IGUT started in 2018. Seismograms were sorted by station and date to create a hardcopy data bank, and then those from large earthquakes with significant damage and casualties, and their larger aftershocks, were chosen to scan. At present, over 600 scanned seismograms from 52 major earthquakes, and their aftershocks larger than M W = 5.0 that occurred in and around Iran and some major and great tele-seismic earthquakes from abroad are available. The current digitization process in IGUT is done manually and is based on waveform vectorization. The provided databank is one of the most important sources of information for researchers in seismology and active tectonics in and around Iran.
