Historical accounts of pre-eruption seismicity of Katla, Hekla, Öræfajökull and other volcanoes in Iceland

JOKULL ◽  
2020 ◽  
Vol 69 ◽  
pp. 35-52
Author(s):  
Páll Einarsson
Keyword(s):  
Seismic Activity ◽  
Wide Spectrum ◽  
Local Population ◽  
Volcanic Hazards ◽  
Ambient Conditions ◽  
Short Term ◽  
Volcanic System ◽  
Instrumental Observations ◽  
Historical Accounts ◽  
Precursory Seismic Activity

Detecting unusual activity leading to the outbreak of a volcanic eruption is of vital importance for the short-term warning to the local population of an impending eruption. The varied volcano types of Iceland and range of ambient conditions at which eruptions occur offer an unusually wide spectrum of volcanic phenomena and volcanic hazards during the initial phase of eruptions. A recent study of eruptions in Iceland during the last four decades of instrumental observations has revealed that all the eruptions had a detectable precursory seismic activity, that under favourable conditions can be used to issue short-term warnings to the surrounding communities. Considerable documentary data also exist for pre-instrumental times extending several centuries back in time, that can be compared to the instrumental experience. This is true in particular for two of the most active volcanoes, Katla and Hekla, that are sufficiently close to the populated areas of the country. All seven confirmed eruptions of Katla since 1625 were preceded by felt earthquakes, beginning one to nine hours before the eruption was detected and two to over twelve hours before a jökulhlaup from this partly sub-glacial volcano reached the inhabited areas. The behaviour of Hekla is quite different. Large eruptions from the main edifice of Hekla since 1510 were generally accompanied by rather weak seismic activity. Earthquakes are usually felt only minutes before the first explosion occurs, in the 1947 case even several minutes after the first explosion of the volcano. Eruptions of the Hekla volcanic system outside the main edifice are, on the other hand, accompanied by considerable seismic activity, and the precursor times may be more than three hours, even much longer. The two historical eruptions of Öræfajökull, in 1362 and 1727, were apparently preceded by felt seismicity, sufficient to alarm the local population.

Conditions of Boarded Out Babies of Wet-Nurses, Colonial Australia

2021 ◽  
pp. 089033442199477
Author(s):  
Virginia Thorley
Keyword(s):  
Family Physicians ◽  
Short Term ◽  
Primary Material ◽  
Substandard Care ◽  
The Social ◽  
Historical Accounts

Wet-nurses themselves rarely left written accounts. In this article, I have reconstructed their experiences and work situations breastfeeding other women’s infants in colonial Australia through examining available sources concerning their employment situations and the fate of their infants when they were boarded out, as they commonly were. The employment of wet-nurses by royal households or prominent families has long been the topic of historical accounts, whereas the situation of the more numerous wet-nurses further down the social spectrum has received disproportionately little examination. In this article, I do not discuss informal, altruistic wet nursing by family or neighbors but, rather, the situation of those women for whom it was an occupation, by its very nature short term. Primary material sighted for this study included a considerable number of advertisements for positions placed by employers, their intermediaries (e.g., family physicians) and wet-nurses themselves, and newspaper reports when the wet-nurse’s children came to the attention of the courts. Death for boarded-out infants who succumbed to inappropriate feeding and substandard care was typically ascribed to “natural causes.”

scholarly journals The implications of vehicle collisions for the Endangered endemic Zanzibar red colobus Piliocolobus kirkii

Oryx ◽  
2021 ◽  
pp. 1-9
Author(s):  
Harry Olgun ◽  
Mzee Khamis Mohammed ◽  
Abbas Juma Mzee ◽  
M. E. Landry Green ◽  
Tim R. B. Davenport ◽  
...  
Keyword(s):  
Road Ecology ◽  
Local Population ◽  
Red Colobus ◽  
Vehicle Collisions ◽  
The Road ◽  
Life History Data ◽  
Natural Predation ◽  
Historical Accounts ◽  
The Impact

Abstract Roads affect wildlife in a variety of negative ways. Road ecology studies have mostly concentrated on areas in the northern hemisphere despite the potentially greater impact of roads on biodiversity in tropical habitats. Here, we examine 4 years (January 2016–December 2019) of opportunistic observations of mammalian roadkill along a road intersecting Jozani-Chwaka Bay National Park, Unguja, Zanzibar. In particular, we assess the impact of collisions on the population of an endemic primate, the Endangered Zanzibar red colobus Piliocolobus kirkii. Primates accounted for the majority of roadkill in this dataset. Monthly rainfall was not associated with roadkill frequency for mammals generally, nor for the Zanzibar red colobus. No single age–sex class of colobus was found dead more often than expected given their occurrence in the local population. The overall effect of roadkill on colobus populations in habitats fragmented by roads is unknown given the lack of accurate, long-term life history data for this species. Our findings suggest that mortality from collisions with vehicles in some groups of colobus is within the range of mortality rates other primates experience under natural predation. Unlike natural predators, however, vehicles do not kill selectively, so their impact on populations may differ. Although a comparison with historical accounts suggests that the installation of speedbumps along the road near the Park's entrance has led to a significant decrease in colobus roadkill, further actions to mitigate the impact of the road could bring substantial conservation benefits.

scholarly journals BrO/SO<sub>2</sub> molar ratios from scanning DOAS measurements in the NOVAC network

2013 ◽  
Vol 5 (2) ◽  
pp. 1845-1870 ◽  
Author(s):  
P. Lübcke ◽  
N. Bobrowski ◽  
S. Arellano ◽  
B. Galle ◽  
G. Garzón ◽  
...  
Keyword(s):  
Molar Ratio ◽  
Optical Absorption Spectroscopy ◽  
Short Term ◽  
Dynamic Changes ◽  
Volcanic System ◽  
Molar Ratios ◽  
Remote Sensing Technique ◽  
Field Campaigns ◽  
Term Field

Abstract. The molar ratio of BrO to SO2 is, like other halogen/sulphur ratios, a~possible precursor for dynamic changes in the shallow part of a volcanic system. While the predictive significance of the BrO/SO2 ratio has not been well constrained yet, it has the major advantage that this ratio can be readily measured using the remote-sensing technique Differential Optical Absorption Spectroscopy (DOAS) in the UV. While BrO/SO2 ratios have been measured during several short-term field campaigns this article presents an algorithm that can be used to obtain long-term time series of BrO/SO2 ratios from the scanning DOAS instruments of the Network for Observation of Volcanic and Atmospheric Change (NOVAC) or comparable networks. Parameters of the DOAS retrieval of both trace gases are given and the influence of co-adding spectra on the retrieval error will be investigated. Difficulties in the evaluation of spectroscopic data from monitoring instruments in volcanic environments and possible solutions are discussed. The new algorithm is demonstrated by evaluating data from the NOVAC scanning DOAS systems at Nevado del Ruiz, Colombia encompassing almost four years of measurements between November 2009 and end of June 2013. This dataset shows variations of the BrO/SO2 ratio several weeks prior to the eruption on 30 June 2012.

scholarly journals Short-term movement patterns, population estimates and breeding biology of an island endemic bird, the Tristan Thrush

2019 ◽  
Vol 27 (4) ◽  
pp. 245-252
Author(s):  
Peter G. Ryan ◽  
Ben J. Dilley ◽  
Delia Davies ◽  
Trevor Glass ◽  
Fitsum Abadi
Keyword(s):  
Total Population ◽  
Data Augmentation ◽  
Local Population ◽  
Population Estimates ◽  
Limited Information ◽  
Short Term ◽  
Main Island ◽  
Island Endemic ◽  
Core Study ◽  
Land Bird

AbstractThe Tristan Thrush Turdus eremita is the only land bird that survived human colonisation of the main island of Tristan da Cunha and is listed as “Near Threatened”. Population estimates are confounded by the thrushes’ inquisitive and gregarious nature as well as limited information on their movements. We report the first measures of nest densities on Nightingale Island: 6 nests·ha-1 in Phylica arborea woodland and 4–5 nests·ha-1 in tussock habitat, which suggests that the population is approximately double the previous estimate. At Inaccessible Island, we individually color ringed 110 thrushes over two months to track their short-term movements and estimate the local population size. Individuals moved up to 950 m along the coast, but 96% of resightings were < 100 m. A Bayesian data augmentation approach estimated that some 260 thrushes visited the core study area, a 200-m stretch of cobble and boulder beach where birds come to drink, bathe and forage. This result suggests that the population on Inaccessible Island also is substantially larger than reported previously. We estimate the total population to be 8000–15,000 Tristan Thrushes. The main need is a population estimate for the nominate subspecies on the main island of Tristan.

Hydrogeochemical temporal variations related to changes of seismic activity at Tenerife, Canary Islands

2021 ◽  
Author(s):  
Cecilia Amonte ◽  
María Asensio-Ramos ◽  
Gladys V. Melián ◽  
Nemesio M. Pérez ◽  
Eleazar Padrón ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Seismic Activity ◽  
Temporal Variations ◽  
Total Alkalinity ◽  
Molar Ratio ◽  
Sampling Point ◽  
Volcanic System ◽  
Mean Values ◽  
Isotopic Analyses ◽  
San Fernando

&lt;p&gt;The oceanic active volcanic island of Tenerife (2034 km&lt;sup&gt;2&lt;/sup&gt;) is the largest of the Canarian archipelago. There are more than 1,000 galleries (horizontal drillings) in the island, which are used for groundwater exploitation and allow reaching the aquifer at different depths and elevations. During a two-year period (July 2016 to July 2018), a hydrogeochemical study was carried out in two galleries on Tenerife (Fuente del Valle and San Fernando) for volcanic monitoring purposes with weekly sampling. Physicochemical parameter of water, such us temperature (&amp;#186;C), pH and electrical conductivity (E.C., &amp;#181;S&amp;#183;cm&lt;sup&gt;-1&lt;/sup&gt;), were measured in-situ at each sampling point and chemical/isotopic composition of the water determined later in the laboratory.&lt;/p&gt;&lt;p&gt;Temperature values showed mean values of 28.1 &amp;#186;C and 19.0 &amp;#186;C for Fuente del Valle and San Fernando galleries, respectively. According to the average pH values, which were 6.30 for Fuente del Valle and 7.13 for San Fernando, and based on the chemical composition, both galleries are sodium-bicarbonate (Na-HCO&lt;sub&gt;3&lt;/sub&gt;) type. E.C. values in both galleries presented high ranges, with mean values of 975 and 1648 &amp;#181;S&amp;#183;cm&lt;sup&gt;-1&lt;/sup&gt; for Fuente del Valle and San Fernando, respectively. The total alkalinity mean value of groundwater from Fuente del Valle gallery was 11.3 mEq&amp;#183;L&lt;sup&gt;-1&lt;/sup&gt; HCO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;, while that from San Fernando was 17.3 mEq&amp;#183;L&lt;sup&gt;-1&lt;/sup&gt; HCO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;. The SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;/Cl molar ratio was 0.59 and 3.4 for the samples from Fuente del Valle and San Fernando galleries, respectively.&lt;/p&gt;&lt;p&gt;The &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O and &amp;#948;D isotopic analyses showed a meteoric origin of groundwaters, with mean values of -6.2&amp;#8240; and -26&amp;#8240; vs. VSMOW for Fuente del Valle and -6.2&amp;#8240; and -21 &amp;#8240; vs. VSMOW for San Fernando. The isotopic data showed a strong interaction with endogenous gases such as CO&lt;sub&gt;2&lt;/sub&gt;, H&lt;sub&gt;2&lt;/sub&gt;S, H&lt;sub&gt;2&lt;/sub&gt;, etc. Regarding the isotopic composition of total dissolved carbon species, expressed as &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;TDIC&lt;/sub&gt;, average values of -0.17&amp;#8240; and 0.26&amp;#8240; were obtained for Fuente del Valle and San Fernando galleries, respectively. These results show an endogenous origin CO&lt;sub&gt;2&lt;/sub&gt; signature, heavier for Fuente del Valle gallery groundwater compared to that of San Fernando.&lt;/p&gt;&lt;p&gt;Groundwater physicochemical parameters exhibited stable values throughout the study period, while significant temporal variations were observed in the total alkalinity, SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;/Cl&lt;sup&gt;-&lt;/sup&gt; molar ratio, &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O and &amp;#948;D. Changes in isotopic ratios coincided with variations observed in the alkalinity and the SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;/Cl&lt;sup&gt;-&lt;/sup&gt; molar ratio. On October 2, 2016, a seismic swarm of long-period events was recorded on Tenerife followed by a general increase of the seismic activity in and around the island. A correlation was observed between some hydrogeochemical parameters in the groundwaters of the galleries, related to observed changes of the seismic activity. This study demonstrates the suitability of monitoring the chemical and isotopic composition of groundwater from Fuente del Valle and San Fernando galleries, as they are sensitive to changes in volcanic activity on Tenerife island. The study of groundwaters associated to a volcanic system can provide information about the magmatic gas input in the aquifer, modelling how the groundwaters flow through the edifice, and offer important geochemical information that could herald a future eruption.&lt;/p&gt;

scholarly journals Relationship between seismicity and eruptive activity at Mt. Etna volcano (Italy) as inferred from historical record analysis: the 1883 and 1971 case histories

1996 ◽  
Vol 39 (2) ◽  
Author(s):  
R. Azzaro ◽  
M. S. Barbano
Keyword(s):  
Seismic Activity ◽  
Historical Record ◽  
Effusion Rate ◽  
Etna Volcano ◽  
Case Histories ◽  
Seismic Behaviour ◽  
Volcanic System ◽  
Prolonged Duration ◽  
Mt Etna ◽  
A Minor

In this paper historical and recent seismological data are analysed in order to investigate the relationship between seismicity and eruptive phenomena at Mt. Etna volcano. The 1883 and 1971 case histories have been proposed because they are significant events in the recent history of the volcano regarding volcanic hazard and show very different evolutions of associated seismic activity and eruption dynamics. The first (1883) represents flank eruptions characterised by high seismic release, short duration and moderate effusion rate whereas the second (1971) can be ascribed to eruptions starting as summit or subterminal events and thereafter developing on the flanks with a minor level of seismicity, higher effusion rate and prolonged duration. The pattern of seismic activity during 1883 and 1971, as inferred from historical record analysis, and the different associated type of eruption may be a result of diverse stress conditions acting on the volcanic system. The interpretation of the seismic behaviour by considering historical eruptions in a systematic fashion will contribute to a clearer understanding of volcanic phenomena at Mt. Etna.

scholarly journals Seismic activity of the earth, the cosmological vectorial potential and method of a short-term earthquakes forecasting

2011 ◽  
Vol 03 (02) ◽  
pp. 109-119 ◽  
Author(s):  
Baurov Yury Alexeevich ◽  
Baurov Alexey Yur’evich ◽  
Baurov Alexandr Yur’evich (Jr.) ◽  
Spitalnaya Alexandra Alfredovna ◽  
Abramyan Ara Arshavirovich ◽  
...  
Keyword(s):  
Seismic Activity ◽  
Short Term ◽  
The Earth

Health Problems Encountered by Short-Term European Volunteers in a Nongovernmental Organization in Cambodia

2022 ◽  
Author(s):  
Jaime Barrio Cortes ◽  
Claudia Rojas Muñoz ◽  
Miguel Ángel Acosta Benito ◽  
Ángela Hidalgo Baz ◽  
Ángel Vicario Merino ◽  
...  
Keyword(s):  
Respiratory Infections ◽  
Wide Spectrum ◽  
Health Problems ◽  
Nongovernmental Organization ◽  
High Rate ◽  
Short Term ◽  
Regular Treatment ◽  
Preventative Health ◽  
Health Course ◽  
Health Related

Short-term volunteers are susceptible to a wide spectrum of morbidities, mostly infectious diseases preventable with general hygiene and preventive measures. This study aimed to identify the health problems encountered by European short-term volunteers collaborating for 1 month with a nongovernmental organization (NGO) in Cambodia and to describe their characteristics. A prospective, descriptive observational study was conducted on short-term volunteers who collaborated with an NGO in Cambodia during August 2018. Informed consent and sociodemographic, clinical, and preventative health-related questionnaire data were provided by 198 volunteers. The health problems encountered were confirmed in a primary care consultation with healthcare professionals. Univariate and bivariate analyses were performed. The median age of the volunteers was 22 years (interquartile range = 21–24), and 64% were women. Some (18.2%) had allergies, 8.6% had preexisting health conditions, and 10.6% were under regular treatment. A total of 77.3% visited a pretravel consultation clinic, 39.9% completed a specific pretravel health course, 21.7% took malaria prophylaxis, 92.4% received hepatitis A vaccination, and 82.3% received typhoid fever vaccination. Medical assistance was sought by 112 (57.3%) of the volunteers. The average number of health problems was 2.5 (standard deviation = 1.5), and the total number of health problems attended by the medical team was 279. The most common health problems were upper respiratory infections (12.2 per 1,000 person-days), wounds (10.8 per 1,000 person-days), and diarrhea (6.3 per 1,000 person-days). Short-term volunteers experienced a high rate of health problems during their stay in Cambodia, but most of the problems were mild and preventable and resolved quickly. Pretravel consultation and specific pretravel health training seemed to increase disease awareness.

Statistical Monitoring and Early Forecasting of the Earthquake Sequence: Case Studies after the 2019 M 6.4 Searles Valley Earthquake, California

2020 ◽  
Vol 110 (4) ◽  
pp. 1781-1798 ◽  
Author(s):  
Yosihiko Ogata ◽  
Takahiro Omi
Keyword(s):  
Real Time ◽  
Case Studies ◽  
Seismic Activity ◽  
Southern California ◽  
Aftershock Sequence ◽  
Earthquake Sequence ◽  
Short Term ◽  
Probability Forecast ◽  
Background Rate ◽  
High Background

ABSTRACT This study considers the possible implementation of the operational short-term forecasting, and analysis of earthquake occurrences using a real-time hypocenter catalog of ongoing seismic activity, by reviewing case studies of the aftershocks of the Mw 6.4 Searles Valley earthquake that occurred before the Mw 7.1 Ridgecrest earthquake. First, the short-term prediction of spatiotemporal activity is required in real time along with the background seismic activity over a wide region to obtain practical probabilities of large earthquakes; snapshots from the continuous forecasts during the Searles Valley and Ridgecrest earthquake sequence are included to monitor the growth and migration of seismic activity over time. We found that the area in and around the rupture zone in southern California had a very high background rate. Second, we need to evaluate whether a first strong earthquake may be the foreshock for a further large earthquake; the rupture region in southern California had one of the highest such probabilities. Third, short-term probability forecast of early aftershocks are much desired despite the difficulties with data acquisition. The aftershock sequence of the Mw 6.4 Searles Valley event was found to significantly increase the probability of a larger earthquake, as seen in the foreshock sequence of the 2016 MJMA 7.4 Kumamoto, Japan, earthquake. Finally, detrending the temporal activity of all the aftershocks by stretching and shrinking the ordinary time scale according to the rate given by the Omori–Utsu formula or the epidemic-type aftershock sequence model, we observe the spatiotemporal occurrences in which seismicity patterns may be abnormal, such as relative quiescence, relative activation, or migrating activity. Such anomalies should be recorded and listed for the future evaluation of the probability of a possible precursor for a large aftershock or a new rupture nearby. An example of such anomalies in the aftershocks before the Mw 7.1 Ridgecrest earthquake is considered.

Sign in / Sign up

Export Citation Format

Share Document