Abstract:A set of 50,000 artificial Earth impacting asteroids was used to obtain, for the first time, information about the dominance of individual impact effects such as wind blast, overpressure shock, thermal radiation, cratering, seismic shaking, ejecta deposition, and tsunami for the loss of human life during an impact event for impactor sizes between 15 and 400 m and how the dominance of impact effects changes over size. Information about the dominance of each impact effect can enable disaster managers to plan for… Show more
“…Fireballs are exceptionally bright meteors produced by the impact of asteroids or comets on Earth's atmosphere and are usually called bolides if they explode midair. Large enough impact air bursts, even if the impactor does not reach the surface, can produce damage and casualties by a variety of mechanisms, especially by wind blast, thermal radiation, and atmospheric shock wave overpressure (Rumpf et al, ), being the latter recently illustrated by the damaging 2013 Chelyabinsk impact (Brown et al, ; Heimann et al, ; Popova & the Chelyabinsk Airburst Consortium, ).…”
The size or energy of diverse structures or phenomena in geoscience appears to follow power law distributions. A rigorous statistical analysis of such observations is tricky, though. Observables can span several orders of magnitude, but the range for which the power law may be valid is typically truncated, usually because the smallest events are too tiny to be detected and the largest ones are limited by the system size. We revisit several examples of proposed power law distributions dealing with potentially damaging natural phenomena. Adequate fits of the distributions of sizes are especially important in these cases, given that they may be used to assess long‐term hazard. After reviewing the theoretical background for power law distributions, we improve an objective statistical fitting method and apply it to diverse data sets. The method is described in full detail, and it is easy to implement. Our analysis elucidates the range of validity of the power law fit and the corresponding exponent and whether a power law tail is improved by a truncated lognormal. We confirm that impact fireballs and Californian earthquakes show untruncated power law behavior, whereas global earthquakes follow a double power law. Rain precipitation over space and time and tropical cyclones show a truncated power law regime. Karst sinkholes and wildfires, in contrast, are better described by truncated lognormals, although wildfires also may show power law regimes. Our conclusions only apply to the analyzed data sets but show the potential of applying this robust statistical technique in the future.
“…Fireballs are exceptionally bright meteors produced by the impact of asteroids or comets on Earth's atmosphere and are usually called bolides if they explode midair. Large enough impact air bursts, even if the impactor does not reach the surface, can produce damage and casualties by a variety of mechanisms, especially by wind blast, thermal radiation, and atmospheric shock wave overpressure (Rumpf et al, ), being the latter recently illustrated by the damaging 2013 Chelyabinsk impact (Brown et al, ; Heimann et al, ; Popova & the Chelyabinsk Airburst Consortium, ).…”
The size or energy of diverse structures or phenomena in geoscience appears to follow power law distributions. A rigorous statistical analysis of such observations is tricky, though. Observables can span several orders of magnitude, but the range for which the power law may be valid is typically truncated, usually because the smallest events are too tiny to be detected and the largest ones are limited by the system size. We revisit several examples of proposed power law distributions dealing with potentially damaging natural phenomena. Adequate fits of the distributions of sizes are especially important in these cases, given that they may be used to assess long‐term hazard. After reviewing the theoretical background for power law distributions, we improve an objective statistical fitting method and apply it to diverse data sets. The method is described in full detail, and it is easy to implement. Our analysis elucidates the range of validity of the power law fit and the corresponding exponent and whether a power law tail is improved by a truncated lognormal. We confirm that impact fireballs and Californian earthquakes show untruncated power law behavior, whereas global earthquakes follow a double power law. Rain precipitation over space and time and tropical cyclones show a truncated power law regime. Karst sinkholes and wildfires, in contrast, are better described by truncated lognormals, although wildfires also may show power law regimes. Our conclusions only apply to the analyzed data sets but show the potential of applying this robust statistical technique in the future.
“…Für eine solche Studie wurde eine Vielzahl von Einschlagsszenarien simuliert, welche die statistischen Eigenschaften von möglichen Asteroideneinschlägen mit unterschiedlichen Orten, Winkeln und Geschwindigkeiten der Asteroiden berücksichtigen. Zunächst wurden daher diese statistischen Verteilungen bestimmt (Abbildung ) . Diese Daten stammen aus Simulationen von Asteroidenbewegungen, die mit Beobachtungen und analytischen Untersuchungen übereinstimmen.…”
Section: Einschlagssimulationen Mit Armorunclassified
“… Einschlagsparameter a) Statistische Verteilungen der Einschlagsparameter (nach ), b) zeigt die Einschlagshäufigkeit je Breitengradband. Breitengradbänder umschließen jeweils den Globus, in Äquatornähe decken sie wesentlich größere Flächen ab als in Polnähe.…”
Section: Einschlagssimulationen Mit Armorunclassified
“… Einschlagsszenarien Kartenausschnitt von Europa mit den Einschlagsszenarien in dieser Region. Die Farben spiegeln den jeweiligen Einschlagswinkel wider (nach ). …”
Section: Einschlagssimulationen Mit Armorunclassified
“…One of the important problems in mineralogical and petrological research of meteorites and asteroids is an assessment of risks of the collisions of such astrophysical objects with the Earth, an estimation of influence of their structure and composition on the power of interaction with the atmosphere and a degree of energy release [1][2][3]. On February 15, 2013, over the Russian city of Chelyabinsk, a large asteroid with a mass of about 10 thousand tons entered the atmosphere at a speed of about 18 km/s [4,5].…”
The internal structural organization and phase composition of a fragment of the Chelyabinsk meteorite have been studied using neutron diffraction, tomography methods, optical microscopy, and Raman spectroscopy. The bulk mineral composition of the meteorite and spatial distribution of different components were determined. In addition to previously found phases of olivine, orthopyroxene, plagioclase and troilite, the obtained data of optical microscopy and neutron diffraction provide evidence of the presence of kamacite phase in the studied meteorite fragment. The heterogeneous distribution of the iron in the olivine and orthopyroxene phases was observed, the morphological calculations were used to analyze the spatial arrangement of metal components.
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