Another earthquake clearly recorded in Timor Leste

While making our data collection run, we are rewarded with sneak peeks of the data we so diligently work to gather.  A significant event occurred mid-way through our time in Timor Leste that occurred ~1200 km north of our array.  

The 17 March, 2015 Molucca Sea event (Mw6.2, 46km deep) taken from the USGS summary page

We visited four stations after this event happened, giving us seismologists a dose of instant gratification!  Well deserved, according to my sweaty, sunburned opinion.

Vertical channel record from stations in Timor Leste.  The P-wave is very
clear as the first arriving energy (look at time axis on bottom of page)
around 22:15, and the surface wave shows up around 22:18.
No S-wave?  Why not (trick question)???????
(top to bottom) Oecussi, Maliana, Same, Los Palos

Mechanics on to go ...

From a special guest writer:

The roads in Timor Leste are pretty rugged by anyone's standard and transporting delicate machinery to such beautiful but isolated locations is always something of a worry (check out the road on the map above !) In these photos Leland is preoccupied with the exhumation of the instrument in Same (in central TL) somewhat concerned that the original road trip might have been a bit hard on it and we had to work some mechanical problems ... who knew this would be foreshadowing ....

On the way back to Dili from Same, the views of the topography along the main highway are perfectly spectacular with many opportunities to look down shear drops from the window of the rapidly moving car. Two intense days of driving were beginning to wear on everyone and everything. The Land Cruiser was flashing oil-pressure warning signs as our driver raced up the hills. With a nod to the medieval surgeons, the driver decided that this meant we should bleed off some oil. Having pulled out the oil filter and run the engine for a while, splattering oil everywhere, and satisfied himself that the car was cured, he drove a few hundred meters before the engine threatened to die. We coasted to a nearby house and transfused a bottle or two of fresh oil.

But there are spectacular views as the road hugs the mountainsides and crosses the high passes between broad valleys.  This south-looking photo brilliantly captures the dynamic geology of Timor - on the left, the Cablac Mountain front is formed by an active normal fault, while the topography on the right leads to the highest point on Timor (Mt. Ramelau).  The structure of Ramelau is composed of variably faulted sedimentary sequences of the Gondwanan and Australian margins whereas the Cablac (broken?) Limestone is associated with the Banda terrane that has been thrust over the top of Timor.  Two drastically different origins, multiple phases of deformation and structural geometries,  one dynamic landscape...

Oecussi upgrade

The western enclave of Timor Leste, Oecussi, is an important region for the country. This area was the original landing point for the Portuguese on Timor Island, and was their first official colony (ca. 1702).  Following Timor Leste's independence from Indonesia in 2002, Oecussi remained with the Timorese.  The area hosts a geologic configuration much different than the rest of the country.  Here it is primarily composed of Banda Arc volcanic rocks - pillow basalts, tuffs, and volcanic breccias - that were derived from hundreds to thousands of kilometers to the north.  The backdrop of the photo below shows the basalts cloaked in the darkness of a looming storm.  Overall, the volcanic terrain looks much like picturesque photos of Hawaii, lush vegetation lines rugged, incised slopes.

Luis Teofilo wrapping up the new and improved Oecussi station.

We came to the Oecussi station that was originally installed in the province capitol, Pante Macassar. Based on previous on-site assessment and careful examination of the data, we were set on moving the station to a more quite location.  Too much local traffic and too close to the ocean (noise).  
We headed to a beautiful location four kilometers to the south in the village of Bobkase.  IPG director Eugenio Soares talked with local IPG staff and a nearby landowner to find us a suitable location. By this time, it was about 10:30am and the temperature was on the rise.  A max temp of nearly 40 C, Cooper and I spending 3 hours on the brink of heat stroke, and a few shovels in the ground led to a sweeeeet installation.  We can truly say we earned this one.

Some like it hot!

Near the town of Pala on the island of Atauro, there is a group of intertidal hot springs from which we collected samples for a project aiming to build a global chemical database of hot spring waters. Luis and Dr. Larry are working to extract the water (with a plastic syringe) and squirt it into a jar. They have to be careful though because the water is a piping ~60 degrees Celsius!

The water flows right out of the ground and the source is physically accessible for sampling only during low-tide. Imagine a gentle, steamy water fountain that has low pressure and would require you to kiss the spout to get a drink.

In order to better understand the geology of the hot spring, Dr. Larry took to smashing some of the in-place igneous rocks and our team (from left: Luis, Cooper and Meghan) gathered round to describe and name the rock and its constituent minerals. 

Some friendly locals stopped by to smile and watch our sampling and rock battering deeds. Apparently, local fishermen and fisherwomen will cook their catches directly in the springs! It's certainly believable - that water was scalding. 

Dawn of a new data

Like this Atauro Island fisherman hauling in his early morning catch, we are in the initial stage of data collection.  After collecting a beautiful set of data from Dare village, a trip from Dili across the Wetar Strait to Atauro yielded another batch. Now, onward to the remaining 28 sites.  

Sunrise on Atauro Island.

Transit to Dili, Timor Leste

After a four month break from field work we are back to visit the seismic array.  Over the course of the North American winter, we have built an archived database of our experiment (hosted by IRIS-DMC), explored lots of scientific literature about our study region, and moved ahead with multiple grant-writing efforts.

This field season marks the growth of our interaction with IPG in Dili. Our entire USC seismic field team has assembled: ASSOCIATE professor Miller (congrats to Meghan and the USC Earth Science Department for promoting her!), Cooper Harris, and Leland O'Driscoll are all in attendance for the first time in Timor Leste.  We also have the pleasure of traveling with Louis Moresi for the week.  Should prove to be an excellent start to the field season.

We have lots of other items to report in greater detail, but here are few highlights of the aforementioned items:

- The current academic term at USC has allowed us to explore various topics of geologic and geophysical research in the Banda region.  The PIs of the project (Miller, Becker, and West) have organized a course that has led us to much better appreciate the dynamic and complex nature of Banda.  Their efforts have allowed the participants (Max Dahlquist, Cooper Harris, Adam Holt, Rob Porritt, Leland O'Driscoll) to tackle diverse and competing hypotheses on the regional geologic composition.  

- We have developed grants to extend our efforts in the region, with specific focus on facilitating hazard reduction and enabling longer-term goals of earthquake monitoring in Timor Leste.  We are competing to obtain a grant from the Society of Exploration Geologists within their Geoscientists Without Borders program.  

Stay tuned for updates from the field...