XEOLXELEK (Elk Lake) fault trench­ing, Vic­to­ria, Cana­da (Pho­to by: Andrew J. Scha­ef­fer)

Geodetic slip modelling of continental earthquakes

Source char­ac­ter­is­tics are a key input in seis­mic haz­ard mod­els. My research aims to make care­ful and detailed obser­va­tions of the earth­quake source. I use InSAR-GNSS joint inver­sion to mod­el the geom­e­try and slip dis­tri­b­u­tion of the host fault. My pre­vi­ous works include the 2020 Mw 6.5 Monte Cristo Range, Neva­da and the 2019 Mw 6.2 Sainyab­u­li, Laos (man­u­script in prepa­ra­tion) earth­quakes, where both rup­tured pre­vi­ous­ly unmapped faults. In both events, we were able to obtain a visu­al­ly and quan­ti­ta­tive­ly good fit between observed and mod­el InSAR data, reveal­ing geo­met­ri­cal­ly com­plex fault seg­ments.

What is the influence of fault structural maturity on rupture behaviours?

Fault struc­tur­al matu­ri­ty describes fault zone evo­lu­tion with incre­men­tal off­sets and is thought to gov­ern cer­tain aspects of rup­ture behav­iours. For instance, earth­quakes on struc­tural­ly mature faults tend to have more local­ized defor­ma­tion along the fault trace. We com­pared the fault matu­ri­ty (using cumu­la­tive off­set as the proxy) with shal­low slip deficit (one minus the nor­mal­ized slip of the sur­fi­cial row of mod­el sub­fault patch­es) of twen­ty-eight con­ti­nen­tal strike-slip earth­quakes. We found that shal­low slip deficit has no cor­re­la­tion with struc­tur­al matu­ri­ty as pre­vi­ous­ly pos­tu­lat­ed, but rather with the mag­ni­tude of the earth­quake. We are fur­ther expand­ing this study by incor­po­rat­ing more events and mul­ti­ple matu­ri­ty prox­ies.

Seismotectonics of Southeast Asia

Dur­ing 2019–2022, mul­ti­ple earth­quake sequences rup­tured the Gold­en Tri­an­gle region (Laos, Thai­land, Myan­mar) in South­east Asia. The NE-trend­ing strike-slip faults accom­mo­date extrud­ed mate­ri­als from the Him­i­layan col­li­sion. How­ev­er, the 2019 Mw 6.2 Sainyab­u­li earth­quake in Laos (the focus of our study) rup­tured a NNW-strik­ing plane (from InSAR). Through inter­na­tion­al col­lab­o­ra­tion, we use mul­ti­ple-event earth­quake relo­ca­tion tech­nique (mloc soft­ware) to char­ac­ter­ize the after­shock dis­tri­b­u­tion and the seis­mo­genic struc­ture of this region which is poor­ly under­stood.

Active tectonics of Panamint Valley, eastern California, United States

Panamint Val­ley has one of the most aston­ish­ing pale­oearthquake allu­vial fan records. Dur­ing my mas­ter’s degree, I con­duct­ed drone sur­veys, mapped allu­vial sur­faces and fault scarps along the Panamint Val­ley fault sys­tem, and incor­po­rat­ed soil chronose­quence with allu­vial fan depo­si­tion­al mor­phol­o­gy to inter­pret the tim­ing of the earth­quakes. We found evi­dences of Late Holocene events which may cor­re­late to the pale­oses­im­ic trench record from pre­vi­ous lit­er­a­ture at the south­ern end of the fault sys­tem; this sug­gests that the most recent earth­quake rup­tured at least ~45–50 km.

Structure from Motion (photogrammetry)

My work has involved Struc­ture from Motion (SfM) pro­cess­ing of data sets of var­i­ous geo­log­ic and ter­rain set­tings. This includes:
(1) Fault scarps and Qua­ter­nary deposits (Panamint Val­ley fault research, data avail­able at Open­To­pog­ra­phy),
(2) Pale­o­seis­mic trench walls
(2.1) XEOLXELEK fault trench­ing col­lab­o­ra­tive work
(2.2) Pale­o­seis­mic trench­ing work­shop in Sagaing, Myan­mar
(3) Bedrock—I designed an inte­grat­ed SfM-bedrock map­ping exer­cise for an advanced remote-sens­ing course.

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