Estimation of Rupture Duration and Mwp Values to Identify Tsunami Generating Earthquakes in Northern Sulawesi

Sulawesi is an area that has a high potential for tsunamis, especially in the North Sulawesi region due to the presence of a Pundungan Mayu subduction resulting from a double collision between the Maluku Sea plate and Halmahera and Sangihe arcs. Analysis of the duration rupture and estimated Mwp has been carried out using the P-wave phase in the North Sulawesi region as one of the tsunami early warning parameters. The data used were teleseismic body wave (300-900) from three earthquake-generating earthquakes with magnitudes above 7 (Sulawesi earthquake November 16, 2008, Celebes earthquake February 11, 2009, Molucca earthquake November 15, 2014) taken from the IRIS waveform catalog with 90 stations BHZ component registrar. The wave used is the P-PP wave phase (20% -90%) with a high frequency bandpass (1-2 Hz) butterworth filter. The results of the duration of the rupture obtained for the Sulawesi earthquake, Celebes earthquake, Molucca earthquake respectively 53.72 s, 52.98 s, 52.50 s. Whereas for Mwp, it has conformity with Mw from the IRIS catalog. So it can be concluded that the tsunami-generating earthquake in Sulawesi has a duration of rupture greater than 50 s which can be categorized as tsunamigenic earthquake (> 50 s) and the use of Mwp can be applied. Keywords : rupture duration, tsunami, Northern Sulawesi, Mwp

Global Regularization of a Restricted Four-Body Problem

In the n-body problem, a collision singularity occurs when the position of two or more bodies coincide. By understanding the dynamics of collision motion in the regularized setting, a better understanding of the dynamics of near-collision motion is achieved. In this paper, we show that any double collision of the planar equilateral restricted four-body problem can be regularized by using a Birkhoff-type transformation. This transformation has the important property to provide a simultaneous regularization of three singularities due to binary collision. We present some ejection–collision orbits after the regularization of the restricted four-body problem (RFBP) with equal masses, which were obtained by numerical integration.

Reflection (e,2e) experiments from surfaces

The application of electron–electron coincidence experiments (e,2e) to solid samples, although begun in the earliest stages of the development of such a spectroscopy, has been extensively exploited only during the past few years and the applicability to surfaces has just started to be pursued. The feasibility of (e,2e) experiments in grazing angle reflection geometry has been recently established for the first time. In spite of the success, the possibility of using the grazing angle (e,2e) technique as a binding energy and (or) momentum spectroscopy of surface states rests on the accurate knowledge of the ionization mechanism. To understand which is the dominant process responsible for the reflection (e,2e) events, under various energies and kinematical conditions, is still an open problem. Two possible mechanisms are envisaged that can generate pairs of correlated electrons in the reflection geometry: a single inelastic collision at large momentum transfer or a double collision (elastic and inelastic) at high and low momentum transfer, respectively. In the present paper are reviewed the results of recent (e,2e) experiments performed at energies from threshold up to 300 eV and with kinematics from normal to grazing incidence. They allow elucidation of the (e,2e) ionization mechanism on surfaces at both grazing and normal impact.