John Francis Clinton

Last Name

Clinton

First Name

John Francis

ORCID

0000-0001-8626-2703

Organisational unit

02818 - Schweiz. Erdbebendienst (SED) / Swiss Seismological Service (SED)

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Publications1 - 10 of 258

Realtime Selection of Optimal Source Parameters Using Ground Motion Envelopes
Jozinovic, Dario; Clinton, John Francis; Massin, Frédérick; et al. (2024)
Seismica
It is increasingly common for seismic networks to operate multiple independent automatic algorithms to characterise earthquakes in real-time, such as in earthquake early warning (EEW) or even standard network practice. Commonly used methods to select the best solution at a given time are simple and use ad hoc rules. An absolute measure of how well a solution (event origin and magnitude) matches the observations by the goodness-of-fit between the observed and predicted envelopes is a robust and independent metric to select optimal solutions. We propose such a measure that is calculated as a combination of amplitude and cross-correlation fit. This metric can be used to determine when a preferred solution reaches an appropriate confidence level for alerting, or indeed to compare two (or more) different event characterisations directly. We demonstrate that our approach can also be used to suppress false alarms commonly seen at seismic networks. Tests using the 10 largest earthquakes in Switzerland between 2013 and 2020, and events that caused false alarms demonstrate that our approach can effectively prefer solutions with small errors in location and magnitude, and can clearly identify and discard false origins or incorrect magnitudes, at all time scales, starting with the first event characterisation.
Seismic constraints from a Mars impact experiment using InSight and Perseverance
Fernando, Benjamin; Wójcicka, Natalia; Maguire, Ross; et al. (2022)
Nature Astronomy
NASA's InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission has operated a sophisticated suite of seismology and geophysics instruments on the surface of Mars since its arrival in 2018. On 18 February 2021, we attempted to detect the seismic and acoustic waves produced by the entry, descent and landing of the Perseverance rover using the sensors onboard the InSight lander. Similar observations have been made on Earth using data from both crewed(1,2) and uncrewed(3,4) spacecraft, and on the Moon during the Apollo eras(5), but never before on Mars or another planet. This was the only seismic event to occur on Mars since InSight began operations that had an a priori known and independently constrained timing and location. It therefore had the potential to be used as a calibration for other marsquakes recorded by InSight. Here we report that no signal from Perseverance's entry, descent and landing is identifiable in the InSight data. Nonetheless, measurements made during the landing window enable us to place constraints on the distance-amplitude relationships used to predict the amplitude of seismic waves produced by planetary impacts and place in situ constraints on Martian impact seismic efficiency (the fraction of the impactor kinetic energy converted into seismic energy).
Systematic Comparisons of Broad-band Velocity and Acceleration Earthquake Records as a Quality Assessment Tool for European Open Strong-motion Data
Cauzzi, Carlo Virgilio; Bindi, Dino; Cambaz, Didem; et al. (2022)
Seismological Research Letters
The Far Side of Mars: Two Distant Marsquakes Detected by InSight
Horleston, Anna C.; Clinton, John Francis; Ceylan, Savas; et al. (2022)
The Seismic Record
For over three Earth years the Marsquake Service has been analyzing the data sent back from the Seismic Experiment for Interior Structure—the seismometer placed on the surface of Mars by NASA’s InSight lander. Although by October 2021, the Mars seismic catalog included 951 events, until recently all these events have been assessed as lying within a radius of 100° of InSight. Here we report two distant events that occurred within days of each other, located on the far side of Mars, giving us our first glimpse into Mars’ core shadow zone. The first event, recorded on 25 August 2021 (InSight sol 976), shows clear polarized arrivals that we interpret to be PP and SS phases at low frequencies and locates to Valles Marineris, 146° ± 7° from InSight. The second event, occurring on 18 September 2021 (sol 1000), has significantly more broadband energy with emergent PP and SS arrivals, and a weak phase arriving before PP that we interpret as Pdiff. Considering uncertain pick times and poorly constrained travel times for Pdiff, we estimate this event is at a distance between 107° and 147° from InSight. With magnitudes of MMaw 4.2 and 4.1, respectively, these are the largest seismic events recorded so far on Mars.
Kalman Filter-Based Fusion of Collocated Acceleration, GNSS and Rotation Data for 6C Motion Tracking
Rossi, Yara Lorena; Tatsis, Konstantinos; Awadaljeed, Mudathir; et al. (2021)
Sensors
The ground motion of an earthquake or the ambient motion of a large engineered structure not only has translational motion, but it also includes rotation around all three axes. No current sensor can record all six components, while the fusion of individual instruments that could provide such recordings, such as accelerometers or Global Navigation Satellite System (GNSS) receivers, and rotational sensors, is non-trivial. We propose achieving such a fusion via a six-component (6C) Kalman filter (KF) that is suitable for structural monitoring applications, as well as earthquake monitoring. In order to develop and validate this methodology, we have set up an experimental case study, relying on the use of an industrial six-axis robot arm, on which the instruments are mounted. The robot simulates the structural motion resulting atop a wind-excited wind turbine tower. The quality of the 6C KF reconstruction is assessed by comparing the estimated response to the feedback system of the robot, which performed the experiments. The fusion of rotational information yields significant improvement for both the acceleration recordings but also the GNSS positions, as evidenced via the substantial reduction of the RMSE, expressed as the difference between the KF predictions and robot feedback. This work puts forth, for the first time, a KF-based fusion for all six motion components, validated against a high-precision ground truth measurement. The proposed filter formulation is able to exploit the strengths of each instrument and recover more precise motion estimates that can be exploited for multiple purposes.
A high and low noise model for strong motion accelerometers
Clinton, John Francis; Cauzzi, C.; Olivieri, M. (2010)
Earthquakes in Switzerland and surrounding regions during 2015 and 2016
Diehl, Tobias; Clinton, John Francis; Deichmann, Nicolas; et al. (2018)
Swiss Journal of Geosciences
This report summarizes the seismicity in Switzerland and surrounding regions in the years 2015 and 2016. In 2015, the Swiss Seismological Service detected and located 735 earthquakes in the region under consideration. With a total of 20 earthquakes of magnitude ML ≥ 2.5, the seismic activity of potentially felt events in 2015 was close to the average of 23 earthquakes over the previous 40 years. Seismic activity was above average in 2016 with 872 located earthquakes of which 31 events had ML ≥ 2.5. The strongest event in the analyzed period was the ML 4.1 Salgesch earthquake, which occurred northeast of Sierre (VS) in October 2016. The event was felt in large parts of Switzerland and had a maximum intensity of V. Derived focal mechanisms and relative hypocenter relocations of aftershocks image a SSE dipping reverse fault, which likely also hosted an ML 3.9 earthquake in 2003. Another remarkable earthquake sequence in the Valais occurred close to Sion with four felt events (ML 2.7–3.2) in 2015/16. We associate this sequence with a system of WNW-ESE striking fault segments north of the Rhône valley. Similarities with a sequence in 2011, which was located about 10 km to the NE, suggest the existence of an en-echelon system of basement faults accommodating dextral slip along the Rhône-Simplon line in this area. Another exceptional earthquake sequence occurred close to Singen (Germany) in November 2016. Relocated hypocenters and focal mechanisms image a SW dipping transtensional fault segment, which is likely associated with a branch of the Hegau-Bodensee Graben. On the western boundary of this graben, micro-earthquakes close to Schlattingen (TG) in 2015/16 are possibly related to a NE dipping branch of the Neuhausen Fault. Other cases of earthquakes felt by the public during 2015/16 include earthquakes in the region of Biel, Vallorcine, Solothurn, and Savognin.
Combining Estimates from FinDer and Virtual Seismologist Earthquake Early Warning Algorithms
Jozinovic, Dario; Massin, Frédérick; Boese, Maren; et al. (2022)
Proceedings of the Third European Conference on Earthquake Engineering and Seismology – 3ECEES
Acoustic Signals of a Meteoroid Recorded on a Large‐N Seismic Network and Fiber‐Optic Cables
Vera Rodriguez, Ismael; Isken, Marius P.; Dahm, Torsten; et al. (2023)
Seismological Research Letters
A common challenge in acoustic meteoroid signal analyses is to discriminate whether the observed wavefield can be better described by line‐source or point‐source models. This challenge typically arises from a sparse availability of observations. In this work, we present an outstanding record of ground‐coupled waves from local large‐N seismic and distributed acoustic sensing (DAS) observations of a meteoroid in Iceland. Our complete data set includes additional regional stations located within 300 km of the meteoroid’s trajectory. The dense large‐N and DAS data allow identification of acoustic phases that are almost impossible to discriminate on sparser networks, including a weak late arrival resolved mostly only by DAS. Using this data set with a new Bayesian inversion model, we estimate the trajectory parameters of one fragment from the meteoroid. With these results we investigate its orbit in the solar system and propose a classification of the Icelandic event as a slow meteoroid of asteroidal origin with an energy on the order of 4–40 GJ, a probable size on the order of centimeters, and an orbit range consistent with the main asteroid belt.
Seismic monitoring and alert in Switzerland: real- and near-real-time products of the Swiss national seismic networks
Clinton, John Francis; Behr, Yannik; Cauzzi, Carlo; et al. (2014)
Proceedings of the 2nd European Conference on Earthquake Engineering and Seismology (2ECEES)

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