Macroseismic information for the seven largest moderate earthquakes of the Charlevoix seismic zone, Quebec, between 1870 and 2021: February 3, 1902, M 4.5; September 30, 1924, M 5.2; January 08, 1931, M 4.9; October 19, 1939, M 5.3; October 14, 1952, M 4.5; August 19, 1979, M 4.8; March 6, 2005, M 4.7

This Open File Report provides the available macroseismic information for the seven largest moderate earthquakes that occurred in the Charlevoix Seismic Zone between 1870 and 2021. These earthquakes and their moment magnitude (M) are: 1) February 3, 1902, M 4.5; 2) September 30, 1924, M 5.2; 3) January 08, 1931, M 4.9; 4) October 19, 1939, M 5.3; 5) October 14, 1952, M 4.5; 6) August 19, 1979, M 4.8; 7) March 6, 2005, M 4.7. Five, possibly six, of these seven earthquakes occurred in the northeast portion of the CSZ, where the largest event of the period, the 1925 M 6.2 earthquake, also occurred. For each locality where the earthquakes were felt, macroseismic information is given and interpreted on the Modified Mercalli Intensity Scale. The original mail questionnaires filled by postmasters for earthquakes no. 3, 4, 5 and 6 are lost. Consequently, the main sources of information are the newspaper accounts except for no. 7 for which web-based questionnaires are available. The macroseismic information from localities in Canada and in the US (from NOAA) are tabulated in Microsoft Excel spreadsheets. Most newspaper clippings that have macroseismic information are included. The Open File also provides Google Earth kmz files that allow the felt information reports to be viewed in a spatial tool.

Macroseismic information for the 1935 moment magnitude 6.1 earthquake, near Témiscamingue, Quebec

The November 1st, 1935, Témiscaming earthquake occurred within 20 km of the town of Témiscaming, Quebec. This earthquake was felt west to Fort William (now part of Thunder Bay), Ontario, east to Saint John, New Brunswick, and south to Kentucky and Virginia. Damaged chimneys were reported in Témiscaming, Quebec, and North Bay and Mattawa, Ontario. In the epicentral region, rockfalls were observed as well as cracks in gravel and sand along the shores of islands and lakes. Some 350 km away from the epicentre, near Parent, Quebec, earthquake vibrations triggered a 30 metre slide of railroad embankment. Numerous aftershocks were felt in Témiscaming and Kipawa during the following months, the largest rated as magnitude ML 5.4 (or mN 4.9). For the main shock and its largest aftershock, this Open File Report provides the available macroseismic information interpreted on the Modified Mercalli Intensity Scale using newspaper accounts as the main source of information for Canada. Macroseismic information from total of 126 localities in Canada and nearly 900 communities in the US (from the NOAA database of intensities) are tabulated in a Microsoft Excel spreadsheet. When available, newspaper clippings are included, together with some original damage accounts, photographs and scientific reports. The Open File also includes a Google Earth kmz file that allows the felt information reports to be viewed in a spatial tool.

Review of Historical Seismicity of West-Central Brazil: Newly Discovered Events and Implications for Seismic Hazard

ABSTRACT. The Pantanal basin seismic zone has experienced earthquakes with magnitudes up to 5.4 mb. New information on historical events was searched for in regional newspapers, especially the "Correio do Estado", Campo Grande, Mato Grosso do Sul State, Brazil. Several small new events, not previously reported in the Catalog of Berrocal et al. (1984), were discovered. Five events had new macroseismic information from different localities allowing magnitudes to be estimated from the felt area. Ten new events were also discovered, each one felt in a single locality. The event of 1906-Oct-24, with previous magnitude 4.2, was felt in a larger area indicating magnitude 4.9 mb. The large event of 1919-June-01, reported in the Catalog with 4.9 mb, was false, and had resulted from joining a local tremor probably due to a meteorite fall in Santa Luzia (GO) with wrong interpretation of records of the RDJ station, Rio de Janeiro, as if they were from the same event in Mato Grosso. The revised catalog for the West-Central Brazil, compared with geophysical maps, shows that earthquakes occur in areas of low velocities in the upper mantle, as well as in areas of positive gravity free-air anomalies. Stress concentration in the upper crust can be explained as due to both lithospheric thinning and flexure.Keywords: historical seismicity, Pantanal, macroseismic information. Revisão da Sismicidade História do Centro-Oeste do Brasil: Novos Sismos Recém Descobertos e Implicações para Ameaça SísmicaRESUMO. A zona sísmica da bacia do Pantanal tem sismos até 5,4 mb. Informações mais detalhadas sobre eventos históricos foram pesquisadas em jornais regionais, especialmente o "Correio do Estado", Campo Grande, Mato Grosso do Sul. Vários pequenos eventos novos foram descobertos que não constavam do Catálogo anterior de Berrocal et al. (1984). Cinco eventos tiveram novas informações macrossísmicas de diferentes localidades, permitindo estimar magnitudes pela área afetada. Foram descobertos dez novos eventos, cada um com informações de uma única localidade. O evento de 24-Out-1906, com magnitude anterior 4,2, foi sentido em uma área maior, indicando magnitude de 4,9 mb. Já o grande evento de 01-Jun-1919, relatado no Catálogo com magnitude 4,9 mb, era falso, sendo resultado da junção de um tremor local, possivelmente devido à queda de um meteorito em Santa Luzia (GO), com interpretação errada dos registros da estação RDJ (Rio de Janeiro), como se fossem provenientes de um único evento em Mato Grosso. O catálogo revisado para a região Centro-Oeste do Brasil, comparado com mapas geofísicos, mostra que os sismos ocorrem em áreas de baixas velocidades no manto superior, bem como em áreas de anomalias ar-livre positivas. A concentração de tensões na crosta superior pode ser explicada tanto por afinamento litosférico, como por flexura.Palavras-chave: sismicidade histórica, Pantanal, informação macrossísmica.

Seismic History of Central North Anatolian Region: New Contribution from Ottoman Archives

Contemporary Ottoman sources bring a major contribution to the description of the seismic activity in the eastern Mediterranean region and are extensively used by historical seismologists. Among these, the documents of the Ottoman State Archives (Istanbul), and more specifically the correspondence of the local governors with the central authorities form a valuable source for the description of the earthquake effects in territories, which were under the Ottoman rule. Especially for the more recent periods, we observe that not only major earthquakes but also small-to-moderate-size events with local effects find their place in these documents. However, due to the complex and insufficiently categorized structure of the archival material, as well as the need for expertize in Ottoman language and history, except the sections covered in the works of N. Ambraseys and C. Finkel and a number of earthquake-specific studies, these documents are not yet fully exploited in the definition of the regional seismic history. In this pilot study, we investigate the Ottoman archive material related to earthquake effects in the central North Anatolian region and search for possible supportive or new contribution to the seismic history of the study area. The period of investigation is the nineteenth century, with occasional data also found for the pre and postperiod. The study revealed supportive information for 15 earthquakes that were already known to previous compilations, and data for 19 earthquakes that we categorize as new events, demonstrating the value of this primary source and the wealth of macroseismic information that can still be extracted, revealing earthquakes so far unknown as well as enriching the descriptive information related to already known ones.

Near-Field Ground Motions from the July 2019 Ridgecrest, California, Earthquake Sequence

The 2019 Ridgecrest, California, earthquake sequence, including an Mw 6.4 event on 4 July and an Mw 7.1 approximately 34 hr later, was recorded by 15 instruments within 55 km nearest-fault distance. To characterize and explore near-field ground motions from the Mw 6.4 foreshock and Mw 7.1 mainshock, we augment these records with available macroseismic information, including conventional intensities and displaced rocks. We conclude that near-field shaking intensities were generally below modified Mercalli intensity 9, with concentrations of locally high values toward the northern and southern termini of the mainshock rupture. We further show that, relative to near-field ground motions at hard-rock sites, instrumental ground motions at alluvial near-field sites for both the Mw 6.4 foreshock and Mw 7.1 mainshock were depleted in energy at frequencies higher than 2–3 Hz, as expected from ground-motion models. Both the macroseismic and instrumental observations suggest that sediments in the Indian Wells Valley experienced a pervasively nonlinear response, which helps explain why shaking intensities and damage in the closest population center, Ridgecrest, were relatively modest given its proximity to the earthquakes.

The URUP EARTHQUAKE SEQUENCE 2012–2013 with magnitude up to Mwreg=7.0 (Kuril Islands)

In July 2012 – November 2013, a series of strong earthquakes occurred near Urup Island (Kuril Islands, Russia). The article analyzes the position of earthquake foci, focal mechanisms, and macroseismic information according to the SF FRC UGS RAS and IMGiG FEB RAS. The entire set of events according to the epicenter and the mechanisms of the source is divided into a swarm of interplate earthquakes in the immersion zone of the Pacific lithospheric plate with a magnitude up to Mw=6.0 and a stronger and deeper event inside the submerged plate with a magnitude Mw=7.0.

The MCS intensity distribution of the devastating 24 August 2016 earthquake in central Italy (MW 6.2)

<p>Here we describe the macroseismic survey of the 24 August 2016 earthquake in central Italy (M_W 6.2). By applying a revised version of the Mercalli-Cancani-Sieberg scale, we estimated the site intensity in more than 300 localities of Lazio, Abruzzi, Umbria and Marche regions, providing the Civil Protection with a quick and robust snapshot of the earthquake. The most severe effects are focused south of the instrumental epicenter, in the Amatrice intermountain basin, where intensity reached 10-11 MCS. Highest damage (area inside 9 MCS isoseismal) is focused in a NNW-SSE belt of the hangingwall of the causative faults, i.e. the southern segment of the Mount Vettore fault system and the northern segment of the Laga Mounts fault system, with northward damage propagation in the far-field. The intensity dataset allows to evaluate a M_W 6.16±0.5, which is very close to the instrumental magnitude, with a seismogenic box striking N161°, mimicking the geological active faults. Epicentral intensity is I_0 10 MCS, I_MAX 10-11. The elevated level of destruction is mainly due to the high vulnerability of buildings, mostly made by cobblestone masonry. Integrating the macroseismic information with the geological, geodetical and geophysical data it is possible to hypothesize a bidirectional rupture propagation (toward NNW and SSE) along the two different faults. It is also possible to attribute the 1639, M_W 6.0 earthquake to the same source of the southern 2016 rupture (northernmost Laga Mounts faults).</p>

The autumn 1919 Torremendo (Jacarilla) earthquake series (SE Spain)

<p>On 10th September 1919 several slightly damaging earthquakes struck the towns of Torremendo, Jacarilla (near Alicante, SE-Spain) and others nearby. Available magnitude estimations for the largest two events of the series are M = 5 approx. They were earthquakes of moderate size and they occurred in a region where similar magnitude earthquakes, thoroughly studied, occurred recently (1999 Mula; 2002 Bullas; 2005 La Paca; 2011 Lorca). This makes these events of interest for a better definition of the regional seismicity. We study their sources from the analysis of the available contemporary seismograms and related documents. A total of 23 seismograms from 9 seismic stations have been collected and digitized. These seismograms contain records for the two main events and several aftershocks of the earthquake series. Finally 44 files, corresponding to 44 recorded single component records from the different events have been processed. The events have been relocated and their magnitudes recalculated. Also, original macroseismic information for these events was recovered. A macroseismic evaluation of the series has been performed. Intensity data points have been recalculated and macroseismic location and magnitude obtained. We conclude that these are the largest earthquakes occurred in the region since the beginning of instrumental recording, with Mw = 5.5 for the largest shock, and that the available data could be compatible with a thrust mechanism related to blind faults in the Bajo Segura region.</p>