Supplementary material to "Pre-collapse motion of the February 2021 Chamoli rock-ice avalanche, Indian Himalaya"

Abstract. On the 7th of February 2021, a large rock-ice avalanche triggered a debris flow in Chamoli district, Uttarakhand, India, leaving over 200 dead or missing. The rock-ice avalanche originated from a steep, glacierized north-facing slope. In this work, we assess the precursory signs exhibited by this slope prior to the catastrophic collapse. We evaluate monthly slope motion from 2015 to 2021 through feature tracking of high-resolution optical satellite imagery. We then combine these data with a time series of pre- and post-event DEMs, which we use to evaluate elevation change over the same area. Both datasets show that the 26.9 Mm3 collapse block moved over 10 m horizontally and vertically in the five years preceding collapse, with particularly rapid motion occurring in the summers of 2017 and 2018. We propose that the collapse results from a combination of snow-loading in a deep headwall crack and permafrost degradation in the heavily jointed bedrock. Our observation of a clear precursory signal highlights the potential of satellite imagery for monitoring the stability of high-risk slopes. We find that the timing of the Chamoli rock-ice avalanche could likely not have been forecast from satellite data alone.

Download Full-text

A massive rock and ice avalanche caused the 2021 disaster at Chamoli, Indian Himalaya

Science ◽

10.1126/science.abh4455 ◽

2021 ◽

pp. eabh4455

Author(s):

D. H. Shugar ◽

M. Jacquemart ◽

D. Shean ◽

S. Bhushan ◽

K. Upadhyay ◽

...

Keyword(s):

Sustainable Development ◽

Numerical Model ◽

High Mountain ◽

Indian Himalaya ◽

Mountain Environments ◽

Glacier Ice ◽

Seismic Records ◽

The Himalaya ◽

Ice Avalanche ◽

Key Questions

On 7 Feb 2021, a catastrophic mass flow descended the Ronti Gad, Rishiganga, and Dhauliganga valleys in Chamoli, Uttarakhand, India, causing widespread devastation and severely damaging two hydropower projects. Over 200 people were killed or are missing. Our analysis of satellite imagery, seismic records, numerical model results, and eyewitness videos reveals that ~27x106 m3 of rock and glacier ice collapsed from the steep north face of Ronti Peak. The rock and ice avalanche rapidly transformed into an extraordinarily large and mobile debris flow that transported boulders >20 m in diameter, and scoured the valley walls up to 220 m above the valley floor. The intersection of the hazard cascade with downvalley infrastructure resulted in a disaster, which highlights key questions about adequate monitoring and sustainable development in the Himalaya as well as other remote, high-mountain environments.

Download Full-text

The Ice Avalanche of the Gemmi Pass (Switzerland)

Scientific American ◽

10.1038/scientificamerican11021895-16550asupp ◽

1895 ◽

Vol 40 (1035supp) ◽

pp. 16550-16550

Author(s):

C. S. Du Riche Preller

Keyword(s):

Ice Avalanche

Download Full-text

Designing Workbook for Teaching Writing Descriptive Text Based on Scientific Approach

JELTIM (Journal of English Language Teaching Innovations and Materials) ◽

10.26418/jeltim.v1i2.26969 ◽

2019 ◽

Vol 1 (2) ◽

pp. 59

Author(s):

Indah Pratiwi ◽

Yanti Sri Rezeki

Keyword(s):

Teaching Writing ◽

English Teacher ◽

Design Development ◽

Seventh Grade ◽

Internal Evaluation ◽

Writing Ability ◽

Good Book ◽

Scientific Approach ◽

Supplementary Material ◽

Analysis Design

This research aims to design workbook based on the scientific approach for teaching writing descriptive text. This research was conducted on the seventh-grade students of SMPN 24 Pontianak. The method of this research is ADDIE (Analysis, Design, Development, Implementation, and Evaluation) with the exclusion of Implementation and Evaluation phases. This material was designed as supplementary material to support the course book used especially in teaching writing of descriptive text. The respondents in this research were the seventh-grade students and an English teacher at SMPN 24 Pontianak. In this research, the researchers found that workbook based on scientific approach fulfilled the criteria of the good book to teach writing descriptive text. The researchers conducted an internal evaluation to see the usability and the feasibility of the workbook. The result of the evaluation is 89%. It showed that the workbook is feasible to be used by students as the supplementary material to support the main course book and help the students improve their writing ability in descriptive text.

Download Full-text

Catalytic Fluorination of Boron Compounds at a Bismuth Redox Platform

10.26434/chemrxiv.9729143 ◽

2019 ◽

Author(s):

Oriol Planas ◽

Feng Wang ◽

Markus Leutzsch ◽

Josep Cornella

Keyword(s):

Transition Metal ◽

Main Group ◽

Group Element ◽

Oxidation States ◽

Boron Compounds ◽

Main Text ◽

Main Group Element ◽

Rational Ligand Design ◽

Supplementary Material

The ability of bismuth to maneuver between different oxidation states in a catalytic redox cycle, mimicking the canonical organometallic steps associated to a transition metal, is an elusive and unprecedented approach in the field of homogeneous catalysis. Herein we present a catalytic protocol based on bismuth, a benign and sustainable main-group element, capable of performing every organometallic step in the context of oxidative fluorination of boron compounds; a territory reserved to transition metals. A rational ligand design featuring hypervalent coordination together with a mechanistic understanding of the fundamental steps, permitted a catalytic fluorination protocol based on a Bi(III)/Bi(V) redox couple, which represents a unique example where a main-group element is capable of outperforming its transition metal counterparts.<br>A main text and supplementary material have been attached as pdf files containing all the methodology, techniques and characterization of the compounds reported.<br>

Download Full-text