The relationship between ML and Mw for small earthquakes (ML < 2-4) in Italy

Abstract

&amp;lt;p&amp;gt;Several authors empirically observed that the scaling between local magnitude ML and moment magnitude Mw computed by spectral methods is not 1:1 for ML&amp;lt;2-4. In particular ML is found to be about proportional to 1.5 Mw but the exact threshold below which this occurs is argued. Such behavior was explained as due to attenuation and scattering along the path or to a minimum limit in the pulse duration or equivalently a maximum limit to the corner frequency of the observed spectra imposed by surface attenuation. The frequency-magnitude distribution of ML estimates provided by the Italian Seismic Instrumental Database (ISIDe) of INGV show a strictly linear behavior with b-value&amp;amp;#187;1.0 down to about ML 1.4 at least. This implies that for Mw the b-value would be about 1.5 below magnitude 2-4 and 1 above. As the frequency magnitude relationship with b-value&amp;amp;#187;1 in terms of Mw is recognized as a general characteristic of seismicity all over the world, based on both empirical and theoretical considerations, the question arises on the reasons of the observed discrepancy for small shocks. One explanation might be the assumption of incorrect seismic wave attenuation properties for the computation of ML, of spectral Mw or both.&amp;lt;/p&amp;gt;

Comparison Between Two Methodologies for Assessing Historical Earthquake Parameters and Their Impact on Seismicity Rates in the Western Alps

“…Resource 7). For the instrumental part we used the instrumental catalogue at the basis of CPTI15, which consists of instrumental locations from Italian instrumental catalogues selected according to a temporal priority scheme and Mw following the procedures in Lolli et al, 2020. The selected events consist of 232 earthquakes, 189 of which are in the period 1000-1980. The magnitude of the latter was determined with both QUake-MD and Boxer and we kept in the catalogue 65 events after applying the following criteria to ensure the reliability of the results: Boxer magnitudes calculated with all IDPs (not from epicentral intensity) and only earthquakes with more than 3 IDP.…”

Use of the 4-Hydroxytriazole Moiety as a Bioisosteric Tool in the Development of Ionotropic Glutamate Receptor Ligands

“…Initially, compounds 6b-c, 7b-c, and 8 were characterized at the major iGluR subgroups in a radioligand binding assay using rat cortical synaptosomes (data for 6a and 7a were previously obtained and are reported in ref. 37 Table 1). Compounds like 6a-6c and 7a showed selective but moderate (μM) activity at AMPA receptors.…”

“…23 Using this strategy, we successfully designed a new class of DHODH (dihydroorotate dehydrogenase) inhibitors, [24][25][26][27][28][29][30][31] AKR1C3 (Aldo-Keto Reductase 1C3) inhibitors, [32][33][34] inhibitors of the canonical NF-κB cascade [35][36] GABA (gamma-aminobutyric acid) analogues [37][38][39] as well as Glu analogues. 40 In light of the promising results obtained in this previous work, and in an attempt to explore the selectivity towards iGluRs, the hydroxy-1,2,3-triazole scaffold was used to bioisosterically replace the distal carboxylic group of Glu. For the AMPA analogues 6a and 7a 41 we previously reported that the hydroxy-1,2,3-triazole scaffold provides the opportunity to place a substituent oriented in two different directions as opposed to the isoxazolol moiety in AMPA.…”