520 research outputs found
Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or causality?
Anecdotes of concurrent eruptions at Etna, Stromboli, and Vulcano (Southern Italy) have persisted for more than
2000 years and volcanologists in recent and past times have hypothesized a causal link among these volcanoes.
Here this hypothesis is tested. To introduce the problem and provide examples of the type of expected volcanic
phenomena, narratives of the most notable examples of concurrent eruptions are provided. Then the frequency
of eruptions at each individual volcano is analysed for about the last 300 years and the expected probability of
concurrent eruptions is calculated to compare it to the observed probability. Results show that the occurrence of
concurrent eruptions is often more frequent than a random probability, particularly for the Stromboli-Vulcano
pair. These results are integrated with a statistical analysis of the earthquake catalogue to find evidence of linked
seismicity in the Etnean and Aeolian areas. Results suggest a moderate incidence of non-random concurrent
eruptions, but available data are temporally limited and do not allow an unequivocal identification of plausible
triggers; our results, however, are the first attempt to quantify a more-than-2000-years-old curious observation
and constitute a starting point for more sophisticated analyses of new data in the future. We look forward to our
prediction of a moderate incidence of concurrent eruptions being confirmed or refuted with the passage of time
and occurrence of new events
Rancang Bangun dan Uji Coba Lapang Pengukur Angin di Atas Platform Coastal Buoy
Sistem kerja instrumen dirancang untuk mengukur data anginyangdapatdiujicobapadaplatformcoastalbuoy berbasisdatalogger.Sistemelektronikterdiriatas ArduinoProminisebagaipusatpengendaliyang memerintahkansensoruntukmengukurdan memerintahkanmodultransmitteruntukmengirimkan data,kemudianditerimaolehrecieveryangdidalamnya terdapatmikrokontrolerpengendaliyaitu,Arduino Prominisebagaipusatpengendalipenyimpanandata. Hasilujikinerjainstrumenmenunjukannilaikorelasialat pengukurkecepatananginadalah0.87denganRMSE 0.51m/s,korelasialatpengukurarahanginsebesar 0.99denganRMSE2.55derajatmataangin.Hasiluji cobalapangdiPerairanTelukPelabuhanRatudiperoleh kecepatananginberkisar0.5"“5.7m/sdidominasiangin timur.KataKunci:Instrumen,angin,rancangbangun,uji kinerja
The anomaly of the CMB power with the latest Planck data
The lack of power anomaly is an unexpected feature observed at large angular
scales in the CMB maps by the COBE, WMAP and Planck satellites. This signature,
which consists in a missing of power with respect to that predicted by the
CDM model, might hint at a new cosmological phase before the standard
inflationary era. The main point of this paper is taking the latest Planck
polarisation data into account to investigate how CMB polarisation improves the
understanding of this feature. With this aim, we apply to the last Planck data,
both PR3 (2018) and PR4 (2020) releases, a new class of estimators able to
evaluate this anomaly considering temperature and polarisation data both
separately and in a jointly way. This is the first time that the PR4 dataset is
used to study this anomaly. In order to critically evaluate this feature,
taking into account the residuals of known systematic effects present in the
Planck datasets, we analyse the cleaned CMB maps using different combinations
of sky masks, harmonic range and binning on the CMB multipoles. Our analysis
shows that the estimator based only on temperature data confirms the presence
of a lack of power with a lower-tail-probability (LTP), depending on the
component separation method, and , for PR3 and PR4
respectively. To our knowledge the for the PR3 dataset is the
lowest one present in the literature obtained from Planck 2018 data considering
the Planck confidence mask. We find significant differences between these two
datasets when polarisation is taken into account. However, we also show that
for the PR3 dataset the inclusion of the subdominant polarisation information
provides estimates which are less likely accepted in a CDM
cosmological model than the only-temperature analysis on the whole
harmonic-range considered
Neogene-Quaternary intraforeland transpression along a Mesozoic platform-basin margin: The Gargano fault system, Adria, Italy
We analyzed field structural data and an offshore seismic-reflection profile and compared them with previously published geological and geophysical data to constrain the tectonic evolution of the Gargano fault system, the kinematics of which have been the subject of contradictory interpretations. Field analyses show that the Gargano fault system consists of NW- to W-striking folds, thrusts, and left-lateral transpressional and strike-slip faults. A set of NW-striking solution cleavage supports the inference of an overall left-lateral kinematic regime for the Gargano fault system. Some synsedimentary structures indicate Miocene-Pliocene contractional and transpressional activity along the Gargano fault system, whereas strike-slip faults affecting Pleistocene conglomerates support a recent, left-lateral, strike-slip activity. The seismic-reflection data show that the offshore prolongation of the Gargano fault system consists of an anticline cut by high-angle faults arranged in a positive flower-like structure, which has mostly grown since middle-late Miocene times along a Mesozoic platform-basin margin. We have schematically reconstructed the tectonic evolution of the Gargano fault system between the middle-late Miocene and the present day. During this period, the Gargano fault system has mostly accommodated contractional to left-lateral transpressional and strike-slip displacements. These displacements are consistent with the regional, Neogene-Quaternary, contractional tectonics across Adria and the Apennines and Dinarides-Albanides fold-and-thrust belts. Some evidence suggests that the Gargano fault system is presently accommodating extensional or left-lateral transtensional displacements. We interpret the Neogene-Quaternary, strike-slip displacements on the Gargano fault system to be connected with the segmentation of the subducted Adriatic slab beneath the Apennines fold-and-thrust belt and with the noncylindrical evolution of this slab (i.e., differential retreating motions), which has undergone differential flexural movements in the adjacent, northern and southern Adriatic compartments
Engineering Of Acoustic Technology For Underwater Positioning Object
Underwater Positioning System (UPS) is a system to track the existence of the position of an object by utilizing the arrival time of the signal measurement. On land, the system uses an electromagnetic signal called GPS. However, because it cannot penetrate water effectively, an acoustic signal is used as an alternative. The purpose of this research is to engineer the control system of data acquisition and underwater acoustic device to measure arrival time (TOA) and apply equation model for underwater sound source positioning system. the effective frequency resonance of the transducer and the hydrophone is at a frequency of 6 kHz. The acquisition control device is able to measure the TOA signal with an error on a digital channel smaller than an analog channel. The difference between the TOA values measured by oscilloscope and acquisition control system is caused by inaccuracy of threshold estimates at the receiver's peak detector circuit. The position of the sound source coordinates obtained from the equation model shows the highest difference in depth point (z) compared to points (x) and (y), caused by the equation model used is limited to four hydrophone units forming a horizontal baseline
Price Level Targeting and Risk Management
Many argue that, in the presence of a lower bound on nominal interest rates, central banks should use a risk management approach for setting policy, which implies commit- ting to a more expansionary policy to deal with uncertainty about the economic recovery. Using a standard model for monetary policy analysis, I study the effects of an uncertain future for both price level targeting and nominal GDP level targeting. The results clarify that, during lower bound episodes, the extent to which policy can overcome uncertainty depends crucially on the choice of policy framework
Nominal GDP Targeting and the Zero Lower Bound: Should We Abandon Inflation Targeting?
I compare nominal GDP level targeting to flexible inflation targeting in a small New Keynesian model subject to the zero lower bound on nominal policy rates. First, I study the performance of optimal discretionary policies. I find that, for a standard calibration, inflation targeting under discretion leaves the economy open to a deflationary trap. Nominal GDP level targeting under discretion, by contrast, provides a firm nominal anchor to the economy. Second, I study simple policy rules and the role of smoothing in the rules. With smoothing, a Taylor-type rule performs as well as a nominal GDP level rule. These result suggest that inflation targeting should not be ditched. Still, it can be improved significantly, by using policy rate smoothing to anchor inflation firmly
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